Issues with new heating zone

powerade

I don't know if my setting is at 4 but I know that is the default. I can't see any details on the ABV but it looks like a BiWorld ABV - 22mm.

rightjob!

Never mind the thermostats,are all the rads scalding when both zones are on?
Is the boiler short cycling?
Take all the trv heads off,close the bypass valve fully turn the heating on for an hour.are the rads roasting?

powerade

I wouldn't say that any of the radiators are evetr scalding. It does not appear to short cycle when both zones are on. I removed all of the TRV heads a couple of days ago.so I will try your suggestion tomorrow to close the bypass valve and run both zones for an hour.

John.G

I think I've found the e manual (couldn't attach as too large). It shows a (integral) by pass valve so you should be reasonably OK in shutting off the ABV, when it is shut just ensure that its not faulty and passing by feeling its outlet, even though you said its on a short piece of piping it should stay far cooler than the flow pipe temperature.
I couldn't find any reference to the CH minimum kw, it does say that the HW minimum kw is 7.14 input = ~ 6.0kw output so I presume that the minimum CH output is similar at ~ 6kw.

Thinking there about zone2 which has two roomstats….a dial type which you think is hard wired to the boiler and a digital which is wired to the zone valve, there could be a mismatch/conflict there, normally you have timer, roomstat, zone valve, boiler enable (by the zone valve end switch) but the digital roomstat may only be controlling the zone valve with the end switch not connected and the dial roomstat may only be controlling the boiler enable.
Before the zoning was fitted it would be correct to go timer, roonstat, boiler enable.
You might carry out a simple test to prove/disprove this. With zone1 off and zone2 on and dial roomstat at minimum see does zone2 motorized valve actuator light up and see if the boiler also fires up, if it doesn't then turn up the dial roomstat and see if the boiler starts up.

For anyone's interest here is a link to the e manual; just google "installation commissioning and servicing instructions wall hung rsf gas fired condensing boiler greenstar i erp" and then select the first PDF file of the same name.

powerade

I have set the ABV to 0 and turned on bith heating zones. There is demand for heat in both zones but the Zone 1 valve dies not appear to have opened, I.e. the actuator light is not illuminated. However, the radiators in both zones appear to be heating up, with the exception of the one in the kitchen.The pipe from the bypass valve to the return is equally as hot as the flow pipe. Should the ABV be set at 0.5 to close it?

John.G

Yes, set to the highest index to close it.
Have you read my edited post #105, it might be interesting to carry out after this present test.

powerade

Zone 2 radiators are belting out heat but the temperature is still slow to climb. The radiators in Zone 1 are not heating equally, e.g. the kitchen radiator and living tmroom radiators were extremely slow to heat.

John.G

The now shut ABV (at 0.5) should give both zones the best possible chance of heat up and the pipe from it to the return should be slowly getting cooler.

powerade

Hi John. I had tested this before and the results were as follows:
1. If the manual dial is set @ a temperature less than the digital thermostat, the manual dial will control the boiler, e.g. digital thermostat set at 32 degrees, manual dial set at 18 degrees, boiler will knock off at 18 degrees
2. If the manual dial is set higher than the digital thermostat, the digital thermostat will control the valve/boiler.
I will test it again later jyst to be absolutely sure but I am reasonably confident that these controls are working as expected.

powerade

I turned off the heating, reset the ABV to 0
5 and turned the heating back on. The temperature soared to 72 degrees, and then went into a rapid anti cycle. It took quite some time to get back up to 65 degrees whereas it got there pretty quickly when the ABV was set at 0. The actuator light for Zone 1 is still off. The pipe from the bypass valve to the return pipe is equally as hot as the flow pipe. The pressure is ever so slightly higher than I have previously noticed it to be (around 1.6). The radiators are very hot in both zones, except the kitchen radiator. The boiler has not cycled, apart from when I changed the ABV setting but the temperature has still only increased by 1 degree in an hour in Zone 2 compared with 2 degrees in Zone 1. That is slow for Zone 1 but it go off to a very slow start when the ABV was set at 0.

John.G

powerade wrote: »

Hi John. I had tested this before and the results were as follows:
1. If the manual dial is set @ a temperature less than the digital thermostat, the manual dial will control the boiler, e.g. digital thermostat set at 32 degrees, manual dial set at 18 degrees, boiler will knock off at 18 degrees
2. If the manual dial is set higher than the digital thermostat, the digital thermostat will control the valve/boiler.
I will test it again later jyst to be absolutely sure but I am reasonably confident that these controls are working as expected.

So you are quite happy that the lower setting on either will close the zone valve (indicator light off) and switch off the boiler?, this means that the dial roomstat is not hard wired to the boiler but is wired in series with the digital roomstat to the zone valve and the zone valve end switch then enables the boiler on/off, technically OK but a bit strange to have two roomstats actuating one zone valve.

John.G

powerade wrote: »

I turned off the heating, reset the ABV to 0
5 and turned the heating back on. The temperature soared to 72 degrees, and then went into a rapid anti cycle. It took quite some time to get back up to 65 degrees whereas it got there pretty quickly when the ABV was set at 0. The actuator light for Zone 1 is still off. The pipe from the bypass valve to the return pipe is equally as hot as the flow pipe. The pressure is ever so slightly higher than I have previously noticed it to be (around 1.6). The radiators are very hot in both zones, except the kitchen radiator. The boiler has not cycled, apart from when I changed the ABV setting but the temperature has still only increased by 1 degree in an hour in Zone 2 compared with 2 degrees in Zone 1. That is slow for Zone 1 but it go off to a very slow start when the ABV was set at 0.

It's strange that zone1 actuator light is off but the zone is still heating up, I can only conclude that the reason for the continued hot by pass pipe is radiation IF the ABV is holding tight.

powerade

The actuator light is off if I have the ABV fully open or closed. In relation to the dual thermostat functionality, I will check again when the heating has cooled down a bit. I am also going to test both zones for one hour again with the ABV fully closed to see if that speeds up Zone 2. I have attached a photo of the pipes & wiring of the thermistats.

John.G

powerade wrote: »

The actuator light is off if I have the ABV fully open or closed. In relation to the dual thermostat functionality, I will check again when the heating has cooled down a bit. I am also going to test both zones for one hour again with the ABV fully closed to see if that speeds up Zone 2. I have attached a photo of the pipes & wiring of the thermistats.

The plot thickens, a ABV is normally a two port valve and would be connected BETWEEN the flow and return, the valve shown is a 3 port and is inserted in the flow pipe, it looks like some form of pressure mixing valve, IMO the flow line should be un restricted so I just don't know how this works, normally a valve inserted like this would be a mixing valve and would be thermostatic.
As you look at your photo above showing flow and return horizontally (I know they are vertical but I cant post your picture showing that ) and pretending the "ABV" is a inverted T so the direction of flow is from left to right and the leg of the T attaches to the short pipe joining the return pipe.....can you say where that arrow is stamped, it on the left or the right (or on the leg) and which direction it is pointing in and we might be able to figure something out.
Also its name, I know you gave it in a previous post.

K.Flyer

John.G wrote: »

The plot thickens, a ABV is normally a two port valve and would be connected BETWEEN the flow and return, the valve shown is a 3 port and is inserted in the flow pipe, it looks like some form of pressure mixing valve, IMO the flow line should be un restricted so I just don't know how this works, normally a valve inserted like this would be a mixing valve and would be thermostatic.
As you look at your photo above showing flow and return horizontally (I know they are vertical but I cant post your picture showing that ) and pretending the "ABV" is a inverted T so the direction of flow is from left to right and the leg of the T attaches to the short pipe joining the return pipe.....can you say where that arrow is stamped, it on the left or the right (or on the leg) and which direction it is pointing in and we might be able to figure something out.
Also its name, I know you gave it in a previous post.

That's a fairly standard two port right angled abv.
Its connected to a piece of pipe coming from the (left) branch on a 3/4" compression "T".
The inlet of the abv is from the underside off that left "T".
So if plumbed correctly, the flow is along the pipe towards the zone valves with the abv before them.

rightjob!

John.G wrote: »

The plot thickens, a ABV is normally a two port valve and would be connected BETWEEN the flow and return, the valve shown is a 3 port and is inserted in the flow pipe, it looks like some form of pressure mixing valve, IMO the flow line should be un restricted so I just don't know how this works, normally a valve inserted like this would be a mixing valve and would be thermostatic.
As you look at your photo above showing flow and return horizontally (I know they are vertical but I cant post your picture showing that ) and pretending the "ABV" is a inverted T so the direction of flow is from left to right and the leg of the T attaches to the short pipe joining the return pipe.....can you say where that arrow is stamped, it on the left or the right (or on the leg) and which direction it is pointing in and we might be able to figure something out.
Also its name, I know you gave it in a previous post.

Thats a bog standard Bi World auto by pass

powerade

I have attached a photo of the bypass that shows the directional arrow. The actuator light on the zone 1 valve does not come on now, regardless of the setting of the ABV. That worries me a bit. The radiators definitely get warmer with the ABV closed and the rate of temperature increase started to improve a little in Zone 1. However, it completly slowed down when the system went into a waiting status, fired up, went into a waiting status again and then a rapid cycle, all of which lasted about 10 minutes. This was repeated 15 minutes later.

John.G

Here ia another bog standard 2 port...http://www.toplinegreenes.ie/plumbing-heating/plumbing/pipe-fittings/valves/biworld/automatic-bypass-valve-22mm

powerade

Yes, I'm pretty sure that's the one .

John.G

Thanks to all, I thought looking at the first photo, that it was a 3 way valve.

John.G

powerade wrote: »

I have attached a photo of the bypass that shows the directional arrow. The actuator light on the zone 1 valve does not come on now, regardless of the setting of the ABV. That worries me a bit. The radiators definitely get warmer with the ABV closed and the rate of temperature increase started to improve a little in Zone 1. However, it completly slowed down when the system went into a waiting status, fired up, went into a waiting status again and then a rapid cycle, all of which lasted about 10 minutes. This was repeated 15 minutes later.

The ABV setting has nothing to do with the actuator, if its not passing/faulty then it should be fully shut off at a setting of 0.4/0.45 if the pump head is a constant 3M.
Re zone1 indicator light, can you just switch both zones off briefly and then switch zone1 back in and ensure its room stat is calling for heat and see if the light comes on.

rightjob!

So whats the issue with the system?

powerade

My heating was spilt into two zones in May of this year. Over the last few months I noticed that Zone 2 was much slower to heat up than Zone 1 when both zones were on together and Zone 2 was taking hours to heat up when it was running on its own. Zone 2 constantly stop/starts when it is running on its own and it would appear that this is a contributing factor to the slowness of the temperature rise in Zone 2, when just that Zone is running. It is unclear as to what is causing the difference in the rate of temperature rise between zone 1 and 2 when they are both running together as the boiler does not appear to stop/start. It has been suggested that there might be dirt in the system. At the moment we are trying to determine the impact of the AB
V setting and TRVs on the heating up of the radiators and it would appear that the radiators get significantly hotter in both zones when the ABV is closed. This marginally improves the rate of temperature rise in Zone 2, when both zones are running. Zone 1 will usually get to temperature on an hour or less but Zone 2 will not. Therefore it will continue to run on its own at which point the stop/start kicks in and the rate of temperature change reduces considerably, e.g. 30 minutes to rise by .2 degree. I think that sums it up

powerade

John, I just did as you suggested but the light is still not coming on.

John.G

Don't know if the LED should light as soon as power is supplied to the actuator (I presume it should) but if the actuator is operating and opening the zone valve then its just a inconvenience.

John.G

powerade wrote: »

My heating was spilt into two zones in May of this year. Over the last few months I noticed that Zone 2 was much slower to heat up than Zone 1 when both zones were on together and Zone 2 was taking hours to heat up when it was running on its own. Zone 2 constantly stop/starts when it is running on its own and it would appear that this is a contributing factor to the slowness of the temperature rise in Zone 2, when just that Zone is running. It is unclear as to what is causing the difference in the rate of temperature rise between zone 1 and 2 when they are both running together as the boiler does not appear to stop/start. It has been suggested that there might be dirt in the system. At the moment we are trying to determine the impact of the AB
V setting and TRVs on the heating up of the radiators and it would appear that the radiators get significantly hotter in both zones when the ABV is closed. This marginally improves the rate of temperature rise in Zone 2, when both zones are running. Zone 1 will usually get to temperature on an hour or less but Zone 2 will not. Therefore it will continue to run on its own at which point the stop/start kicks in and the rate of temperature change reduces considerably, e.g. 30 minutes to rise by .2 degree. I think that sums it up

I think its no harm to add that when you ran zone1 on its own and shut off 2 rads (only 3 "on line") the boiler was cycling as one would expect with a off anti cycle time of 5 mins but the cycling time/temps when cycling on zone2 were inconsistent?.

powerade

Yes, the valve appears to be operating fine. The LED was working up until yesterday so it seemed strange that it should suddenly stop working. In the scheme of things, hiwever, I can live without it:):)

John.G

So now that the ABV is closed have you established if zone2 (with zone1 off) rads are "roasting" and what is happening with anti cycle times/boiler temperatures when the boiler starts to cycle as per normal.

rightjob!

Close the bypass fully
Call for heat on both zones,turn both stats up to max,trv heads off and presuming the lockshields aren’t throttled right down.
If all the rads are roasting its good.
If its the temperature on the stat you are looking at and all rads are roasting its undersized rads/heat loss ect

powerade

John, see post number 118. Now that I can use the info function on the boiler I can see that when the temperature reaches 69 degrees (Zone 2 on) the pilot light will stsy on but the status changes to "System Waiting". It will stay on this status for around 4 minutes. The status then changes to "System heating up" the temperature soars to 70 degrees and the status changes again to "System waiting". This will last another 4 minutes and then the status will change to "anti rapid cycle" which lasts for about 2 minutes. Then the heating comes back on. This cycle was repeated after 15 minutes and I saw it happening with Zone 1 the other day. I need to run the two zones together again to for a bit longer, as suggested by right job

powerade

Just to re-iterate a couple of points:
1. When the heating temperature was controlled by the living room thermostat in Zone 1, before it was split into two zones, if the temperature was 22 degrees in Zone 1 it would be 24 degrees in what is now Zone 2. So, if we assume that the starting temperature was the same in both zones, the radiators could not be undersized. It would also indicate that Zone 2 was heating up more quickly than Zone 1 (now it's the complete opposite). Hence the reason why I decided to split it into two zones.
2. Zone 2 is extremely well insulated.
I appreciate the logic that if the radiators are scalding but the temperature is not rising as expected, then the radiators must be undersized or there must be heat loss from somewhere. Today is the first day that I would say that the radiators in Zone 1 felt really warm so I do need to test that further.

John.G

powerade wrote: »

John, see post number 118. Now that I can use the info function on the boiler I can see that when the temperature reaches 69 degrees (Zone 2 on) the pilot light will stsy on but the status changes to "System Waiting". It will stay on this status for around 4 minutes. The status then changes to "System heating up" the temperature soars to 70 degrees and the status changes again to "System waiting". This will last another 4 minutes and then the status will change to "anti rapid cycle" which lasts for about 2 minutes. Then the heating comes back on. This cycle was repeated after 15 minutes and I saw it happening with Zone 1 the other day. I need to run the two zones together again to for a bit longer, as suggested by right job

To my simple way of thinking if you only need say 2 or 3 kw of rad output then this boiler does some strange things which I will post later, to me this is absolutely crazy, as I said previously a oil fired boiler which runs flat out can easily supply around 2 kw even if does cycle like mad. More later.

powerade

I totally agree John and I have spent quite a lot of money on a system that is costing me more than my old boiler with absolutely ho heating controls......

John.G

This is from the e manual or your own hard copy:

"Table 33, System Waiting; Primary flow temperature above temperature set point.

Anti rapid cycle mode. • The boiler has commenced anti-cycle period for CH. Can be adjusted in boiler settings (2.3b). • Default 5 Minutes


Apoligies: Anti fast cycle should have been anti rapid cycling so no connection to hot water demand


Did the off time exceed 5 minutes?, you mentioned that this cycle was repeated after 15 minutes and what was the boiler flow temperature at its lowest point?.

powerade

There were two consecutive system waiting periods which amounted to 8 minutes followed by one anti rapid cycle which was 2 to 3 minutes so the total off time was approx 11 minutes. 15 minutes later the temperature went up to 69 degrees again and the 11 minute off cycle kicked off again.

John.G

Thanks but did you notice what the lowest boiler flow temperature was during all these periods.

powerade

Sorry John, I think it was 58 degrees.

powerade

It would appear that the radiators get a lot hotter with the ABV closed and that improves the rate of temperature increase in Zone 2. It is still rubbish, however, compared with Zone 1 which took 75 minutes to rise by 5 degrees while zone 2 has taken 190 minutes to rise by the same value. I know that the system is shutting down when the primary flow temperature is above the set temperature point and I also know that this happens when Zone 2 is running on its own or if I turn off any radiators in Zone 1. What I don't understand is how the temperature of the water returning to the boiler can be higher than the temperature that it is being pumped out at, if I am understanding this correctly. Is the boiler not programmed to heat the water for the radiators to 65 degrees and, if that is the case, how can it come back hotter than it was when it left?

rightjob!

powerade wrote: »

It would appear that the radiators get a lot hotter with the ABV closed and that improves the rate of temperature increase in Zone 2. It is still rubbish, however, compared with Zone 1 which took 75 minutes to rise by 5 degrees while zone 2 has taken 190 minutes to rise by the same value. I know that the system is shutting down when the primary flow temperature is above the set temperature point and I also know that this happens when Zone 2 is running on its own or if I turn off any radiators in Zone 1. What I don't understand is how the temperature of the water returning to the boiler can be higher than the temperature that it is being pumped out at, if I am understanding this correctly. Is the boiler not programmed to heat the water for the radiators to 65 degrees and, if that is the case, how can it come back hotter than it was when it left?

Is the boiler set to 65?could be set at 80

Is zone 2 rads roasting when its on?would all rads heat up roughly to the same temperature ?

John.G

Increasing the boiler set point will certainly increase the rad output.

Powerade, what evidence have you got that the boiler return temperature is > the flow temperature.

powerade

The boiler is set to 65 degrees and I understand that is the optimum setting for the condensing function of the boiler. I think that all of the radiators, with the exception of the one in the kitchen heat up to the same temperature but not necessarily at the same rate. If I increase the set temperature I appreciate that will heat the place up more quickly but it won't resolve the rate of increase differential between the two zones and it won't resolve the shut down issue, will it?
My understanding is that the temperature that I see displayed on the boiler is the water temperature in the pipe as it is returned to the boiler. I think my plumber told me that. When it gets to 69 degrees the system will always shut down. When it tries to heat up again it can go as high as 72 degrees so it will shut down again as the water is still too hot. Then it will rapid anti cycle.

John.G

The displayed temperature is the FLOW temperature.I must look at the e manual in a minute but I don't think you can even see the return temperature in the menu tables.
Will get back re radiator temperatures.

Yes, the only measured/displayed CH temperature is the Flow.

Re radiator temperatures. radiator outputs are now based on a "50 deg" rating which is the mean radiator temperature minus the required room temp, 20C is generally used. so if you had a radiator with a flow temp of 75c and a return temp of 60C, the mean is 67.5C, 67.5-20 = 47.5c so you have a "47.5C" rad which will emit (47.5/50)^1.3 or 94% of a 50 deg rad and so on. Now you have a flow temp of 65c and assuming a return temp of 50 then you have a ((65+50)/2)-20, a 37.5 deg rad which will only emit 68% of its 50 deg rated output, if you now increase the flow temp to 75c you will get (as shown above) 94% output of a 50 deg rad but you will get a increase of ~ 38% over your present 65C flow temp. That should satisfy your zone2 problems or you could just increase it to 70c as a interm measure and see how you get on. we can look at the condensing effects later on, if you have a infra red scanner it would be very helpful in establishing the return (and flow) temps for comparison.

The flow pipe is the "leftmost" pipe coming out of the bottom of the boiler and the return is the "rightmost" pipe returning to the boiler, I think, items 2.2 and 2.6 in your manual. You might just feel them with your hand tc confirm that they have been connected in properly first day and also you can get a very rough idea of the temperature difference between them.

powerade

The flow a nbd return pipes are located at the top of my boiler, I believe, and were newly installed when the heating was split into the two zones. The left pipe is definitely hotter than the right pipe but I have no idea what the temperature differential might be. I do have an infer red scanner but the temperature reading is jumping all over the place. I appreciate that if I increase the flow temperature that Zone 2 should heat up more quickly so I will try it later as I am.just running Zone 1 right now. The ABV is set at 0.35 and the radiators are roasting which is good. I will be interested to see if the boiler shuts down more quickly when I change the flow temperature, what do you think? I spoke to Worcester Bosch today about changing the minimum and maximum KW output of the system. Unfortunately the minimum is already set to 7.0 and it cannot be set any lower.

John.G

I would just increase it to 70C now and see what happens.

powerade

I had already changed the temperature to 75 degrees before I saw your post. The rooms definitely feel warmer (but not cosy like zone 1) when you walk into them and the radiators are roasting but there is only a marginal change in the rate of temperature change. The plumber should be out tomorrow, in theory, and you never know, balancing the system might make a difference.

John.G

It may make a difference when both zones are opened but if they are uniformly hot then ??.

Have you noticed/tested on zone2 only when it starts to cycle, make a note of various times etc and most importantly of all note the minimum temperature during a couple of cycles, if the minimum is not less than 63/65C (with a setpoint of 75C) then that is fine and is just as "good" as a constantly cycling oil fired boiler which has a boilerstat hysteresis of 10/12C.

re that heat scanner you've got, is that jumping around if measuring say the ambient temp or if you take cover off a boiling kettle does it give a steady measurement?, if so you might put a bit of black insulation tape on any pipe you want to measure and point the gun at this, it would also be useful for getting a comparison between the flow/return on each rad.

powerade

John, I will come back to you on both of the points that you have raised. This morning I am seeing a dramatic change and I really do not understand why. I turned both zones on at 8.55 using the On programme. In the space of 9 minutes, the temperature in Zone 2 increased by .4 of a degree which is remarkable. After 25 minutes it increased by 1 2 degrees which is still significantly less than Zone 1 but a vast improvement on previous performance. So what's changed? Yesterday I tried to lower the minimum CH KW output but it wouldn't go any lower than 7.0 which It had already been set at. So, in principle, no change. I looked at the max CH KW setting and the pump head but I made no changes. I changed the temperature to 75 degrees last night and ran the heating for approx 1 hour. I then put it back to 65 degrees. The ABV has been set at 0.35 since yesterday morning. I normally use The all day programme when I am testing instead of the On programme. I cant see how any of this would impact Zone 2 but something clearly has. I am going to let both zones run until Zone 2 has reached temperature as I want to see how long it takes with no anti cycling/System shutdowns. Watch this space.......

powerade

With one step forward we take two steps back. The boiler cycled after 65 minutes with both zones on. The temperature dropped to 48 degrees before the boiler fired back up again. The radiators had all cooled down substantially and neither zone had reached temperature. It is now taking ages for the temperature to climb back up again. Where is the logic in all of this? I have seen numerous other posts regarding WB combi boilers and problems with slow temperature rises and constant system shutdown/rapid and cycles. I have not seen one thread, however, with a final solution, possibly because there are multiple factors involved . Still, I suppose that there is an improvenent in Zone 1 but I would love to know what's behind it so that I know what to do if/when it happens again.

powerade

That should read improveme nbt in Zone 2.

John.G

If the boiler was firing at full output for 65 minutes then it would point to the rads emitting ~ 20 kw which seems very improbable as it only takes ~ 4.5 kwh to heat the water contents of say 75 litres from 20 to 70C, my own 20 kw boiler only takes 20/25 minutes from cold to heat up from 20 to 75c with all zones on so I would think that your boiler was not firing at full output for this period, more like 12/15 kw.

I can only suggest for the moment that you carefully note down the system waiting time, water heating time etc and the temperatures.

What is the max output range rated to? you looked at that you said in another post.You could also range rate (max output) down to 12kw just to see what affect this has because all the posts that I have read seem to suggest that a partial solution, at least, is to de rate the boiler down to match the installed radiator outputs.

Edit: The boiler more than likely DID modulate down after x minutes and it was only when the rad demand was lower than the boiler minimum output that it cut out after 65 minutes.
Altough it is very difficult to see how this occurred if both zones were still calling for heat and the rads were only outputting < 7 kw.