central heating zoning controls and TRVS

beolight

Looking at fitting TRVS on my rads but a bit confused

current set up in hot press only allows all radiators on or off with only temperature control being the control on boiler

would like to set up 3 zones i.e upstairs/downstairs radiators and water. is it possible to do this now

would like then to have room stat fitted upstairs and downstairs which would control heating in these zones

fitting TRVS i presume will be secondary control

if zoning not possible how would TRVS operate with a room stat? would room stat fitted downstairs knock out rads upstairs when desired temparature reached? or do i need 2 room stats ie upstairs and downstairs

is fitting a cylinder stat a better option?

PeteHeat

Hi,

Depending on access to the pipes and wiring three zone system is possible,
Upstairs, downstairs, cylinder and boiler interlock.

Good info available here http://www.sei.ie/Grants/Home_Energy_Saving_Scheme/homeowner/About_the_Measures/Heating_Controls.pdf

Grants are available from SEI home Energy Scheme.

.

youtheman

If you want three zones then it really depends on how your house is plumbed. Mine, for example, the outlet comes off the boiler, through a tee, one side being upstairs and the other downstairs. The upstairs is then split again (under the floorboards) to the upstairs radiators and the hot water cylinder. So I can't readily make my system into a three zone system.

Modern houses are designed from scratch to be zoned, the outlet from the boiler goes into a manifold where you have your zone valves, and then feed to the respective radiators and hot water cylinder.

As regards TRVs, you shouldn't fit these in a room with a thermostat as they will be working against each other.

PeteHeat

Hi Youthman,

I agree every system is not suitable for zoning especially older ones.

Did you consider fitting a two port valve at the cylinder ?

Not three independent zones however no water circulating through the cylinder coil unless needed which although marginal should improve efficiency a little.

.

davelerave

if you're combining trvs and main stats you would prob. fit manual rad valves(left open)in stat location.i think then the main stats will function as high-limit stats( like setback but not accurate)

youtheman

PeteHeat wrote: »

Hi Youthman,

I agree every system is not suitable for zoning especially older ones.

Did you consider fitting a two port valve at the cylinder ?

Not three independent zones however no water circulating through the cylinder coil unless needed which although marginal should improve efficiency a little.

.

Pete,

If I wanted to convert my system to a three zone system then I could easily run a separate feed from my boiler to the cylinder (they are quite close). A small piping mod (i.e manifold with three valves) at the boiler outlet would complete the job.

My system was originally installed in 1991. My recent upgrade consisted of a new condensing boiler, TRVs for the upstairs bedrooms and a programmable room stat for the main living room downstairs. The 'techno-phobe' in me is inclined to go for all the bells and whistles, but my wife can hardly get her head around the single room-stat. There's no way she could handle a three zone system (three zones, maybe four switches per zone = 3 X 4 x7 = 84 combinations). It's a bit like a modern video recorder, some people just use 5% of the available functionality.

crosstownk

youtheman wrote: »

It's a bit like a modern video recorder, some people just use 5% of the available functionality.

Time to get Sky+

Seroiusly, while the mathematical combinations exist you will not need them in a practical application. Just set the TRVs once the room temp is what you want. Listen to the TRVs - they hiss when they are close to closing. Once the TRVs are set you shouldn't need to go near them again. Ensure that your system is correctly balanced.

My stats are in common areas - hall & landing - and they are set to 1°C more than the average temperature in the rooms. The only problem I encounter is when the downstairs circuit is on a few hours before the upstairs. The heat rising from the hall to landing can heat up the landing to the stat's set temperature but the upstairs rooms are below the set temp - this can shut off the upstairs circuit prematurely. I should probably offset the upstairs temperature setting to allow for this but I haven't gotten round to that yet.

beolight

what does the 2 port valve mentioned above do?

PeteHeat

Hi,

The two port valve can be controlled with a stat on the cylinder to stop the water circulating through the cylinder coil when the cylinder has reached the set temperature.

The configuration is used a lot when the cylinder has solar as heat source.

.

OB1CAN

youtheman wrote: »

If you want three zones then it really depends on how your house is plumbed. Mine, for example, the outlet comes off the boiler, through a tee, one side being upstairs and the other downstairs. The upstairs is then split again (under the floorboards) to the upstairs radiators and the hot water cylinder. So I can't readily make my system into a three zone system.

Modern houses are designed from scratch to be zoned, the outlet from the boiler goes into a manifold where you have your zone valves, and then feed to the respective radiators and hot water cylinder.

As regards TRVs, you shouldn't fit these in a room with a thermostat as they will be working against each other.

Hi YOUTHEMAN,

I was wondering could you help me ?

I just bought an 80 year old house.There's a new BAXI SOLO boiler fitted. There's rad in the 2 rooms down stairs and 1 in the hall and 4 upstairs incuding the bathroom. I was gonna fit TRV's to all the rads except the bathroom & hall to try and improve economy ... Then I saw your reply and it included zones .. I would love to have the upstairs & downstairs divided.. Can I attach a programmable yoke to the BAXI ? Is there a lot of work in creating zones..ie. labour etc ..Any advice appreciated..Thanks .. OB .. Do you do call out's in the cork city area , lol ..

youtheman

The first question I would ask is : where do you want to control the temperature. Are you happy to just control the temperature in the main living room, or do you want the added option of controlling the temp upstairs or in other rooms (or zones).

The easiest solution, and its the one I did, is as follows:

1. add a programmable room stat in the living room. It can be either hard wired back to the boiler, or if its a old house and you can't run wires then you can get a wireless thermostat. This will give you total temp control in this room, and can also be timed when to turn the boiler on/off.

2. add TRVs to the bedrooms upstairs. Advantage : No wiring modifications required. You can set a lower temp for the bedroom (typically 18 degrees C). Disadvantage : TRVs will not command your boiler to come on/off. The TRVs will only control the room temp if the boiler is already called 'on' from the thermostat described in 1 above.

3. you just need to check that you have 'minimum flow control, either with a special pressure regulating valve, or just with a radiator with no TRV. My new boiler had this valve already incorporated.

The other option is zoned valves and separate thermostats. But it will most probably require wiring and piping mods.

My programmable thermostat cost 70 euros, and each TRV was 15 euros. So my upgrade cost less than 150 euros (I fitted them myself).

OB1CAN

The easiest solution, and its the one I did, is as follows:

1. add a programmable room stat in the living room. It can be either hard wired back to the boiler, or if its a old house and you can't run wires then you can get a wireless thermostat. This will give you total temp control in this room, and can also be timed when to turn the boiler on/off.

2. add TRVs to the bedrooms upstairs. Advantage : No wiring modifications required. You can set a lower temp for the bedroom (typically 18 degrees C). Disadvantage : TRVs will not command your boiler to come on/off. The TRVs will only control the room temp if the boiler is already called 'on' from the thermostat described in 1 above.

3. you just need to check that you have 'minimum flow control, either with a special pressure regulating valve, or just with a radiator with no TRV. My new boiler had this valve already incorporated.

The other option is zoned valves and separate thermostats. But it will most probably require wiring and piping mods.

My programmable thermostat cost 70 euros, and each TRV was 15 euros. So my upgrade cost less than 150 euros (I fitted them myself).

...................
OK ..So it would work like .. Thermostat in TV room where we spend our time would control the boiler on/off when the desired temp is reached... All the while , while the TV room is heating , so are the bedrooms....So I need to fit a stat downstairs and trv on all other rads...But that means the boiler will in the 'on' position for most of the evening ( but I guess it's only coming on when needed ? right ? ) ...

For starters and just finding my way around this old house this should get me going... Can you tell me where I'd pick up the thermostat and trv's...
I just downloaded the installation manual for the BAXI SOLO BOILER and it can accept a Thermostat ...

So I think i should be rock'n rolling there ? Ya ?

Thanks in advance for your help YTM !

youtheman

You're picked up the salient points, except for one thing. If the boiler is timed to come on, then it's really only 'on' while the room temp is below the set point. When the room reaches the desired temp then it will switch off. So it will switch on/off all day to regulate the temp to what you want.

My wife still can't get her head around the 'new ' system. This is how the conversation goes:

Her : I'm cold, why is the heating off.

Me : It's not off.

Her : It is off, the radiators are cold.

Me : the radiators are cold because the room temp is above the set point.

Her : well turn it up.

Me : what temp do you want.

Her : Just turn it up.

Me : I can control the temp to 0.1 degrees C. Tell me exactly what room temp you would like.

Her : Just turn the fu*king temp up.

So she goes to the thermostat and turns it up to 30 degrees (which it can never reach). So essentially she is turning it to constantly on, until she passes out with the heat and then she turns it down to 10 degrees, so it is constantly off. I'm having a hard time trying to convince her to just ADJUST THE SETPOINT SLIGHTLY

youtheman

Forgot to mention that you can get these thermostats in B&Q, or any decent electrical hardware suppliers.

OB1CAN

OK YTM...

Just reading the last message...I thought I had it clear in my reply but I'm missing something...Our house is empty during the day..So , I'll program the boiler to come on between , lets say 5pm and 11am , but only to reach a certain level via the room stat.... Is this correct ? Therefore maintaining a comfort level through out the evening...Only occassionally tweaking it ... Meanwhile in another part of the galaxy (the gaffe) .. the TRV's are also enjoying the feed from the boiler ....

Is the above logic correct.. Also how efficient is it .. ( in your opinion )

OB1 in Cork City and heading to bed now...

Again thanks

youtheman

Yup, you have it.

I program my system to have a setpoint of 20 dgrees at 7.00 am and 10 degrees at 8.00 am. So it comes on between 7 and 8, but will switch of if the room goes above 20 degrees.

Any you can repeat this logic for up to 4 cycles per day.

My programmable stat is a '7 day' unit, so I can have 4 different cycles for each of the 7 days (28 separate permutations).

Right, I'm off for some kip too.

OB1CAN

youtheman wrote: »

Yup, you have it.

I program my system to have a setpoint of 20 dgrees at 7.00 am and 10 degrees at 8.00 am. So it comes on between 7 and 8, but will switch of if the room goes above 20 degrees.

Any you can repeat this logic for up to 4 cycles per day.

My programmable stat is a '7 day' unit, so I can have 4 different cycles for each of the 7 days (28 separate permutations).

Right, I'm off for some kip too.

Hi YTM,

Can I bother ya some , please.

I was in OB plumbing today in cork. The TRV's they had were DRAYTON and have a 'return' valve for € 12 plus VAT .. I think these are the ones I need.

Now the one big question is the wireless room stat.... Because I'm gonna use TRV's in the beds upstairs , I only have 1 zone in effect... They recommended a unit that was programmable etc for a single channel.. question .. Am I right in thinkinig that this unit will replace the old fashion 'dial' / timer for the gas boiler now... So the stat with the keypad on the wall and all the whistles is also the main controller ????

???

I'm using a baxi solo boiler for heat only... so there's no hot water issues here.. just heating...I understand the trvs...I know i need the stat in the room which will control the boiler .. Am I right here ?

Regards and thanks,

OB

youtheman

My 'old' system had a separate mechanical 'timer' next to the boiler, and a separate 'dial' thermostat in the hall. I removed both and replaced with a single 'Drayton Digistat +3' single channel programmable room stat (in the living room).

So I had to run a twin core cable from the boiler to the new stat.

So have a look at the position of your existing stat, you maybe able to use the existing wiring. Or you may have to run a new cable. Or worst case go for a wireless stat so no wiring required.

OB1CAN

youtheman wrote: »

My 'old' system had a separate mechanical 'timer' next to the boiler, and a separate 'dial' thermostat in the hall. I removed both and replaced with a single 'Drayton Digistat +3' single channel programmable room stat (in the living room).

So I had to run a twin core cable from the boiler to the new stat.

So have a look at the position of your existing stat, you maybe able to use the existing wiring. Or you may have to run a new cable. Or worst case go for a wireless stat so no wiring required.

The more I read on these things .. Well here we go.. There is no stat in the house.. Just a new heat only boiler ... And the usual dial mechanical on/off/timed/constant switch that all gas boilers would have been fitted with years ago.....

In what you said above describes my question and dilemma.. When buying the wireless stat it comes with a programmable pad.... Looking at the installation manual , it looks like this will replace the old dial controller and also receive the temp from the stat....So there fore the pad will tell the boiler when you come on and off like the old mecanical unit but also regulate the temp while it is in an 'on' cycle mode....

Am I making sense....

Thanks and regards

OB

OB1CAN

youtheman wrote: »

My 'old' system had a separate mechanical 'timer' next to the boiler, and a separate 'dial' thermostat in the hall. I removed both and replaced with a single 'Drayton Digistat +3' single channel programmable room stat (in the living room).

So I had to run a twin core cable from the boiler to the new stat.

So have a look at the position of your existing stat, you maybe able to use the existing wiring. Or you may have to run a new cable. Or worst case go for a wireless stat so no wiring required.

Or should I ?

Buy a programmabe timer switch to replace the old dial one , program in my cycles. Then just connect a basic wireless room stat to create the up / down set level of the room.. in effect the basic wireless stat will be a make break switch ..

Thanks

youtheman

There is no doubt you can get it to work like you want. It's just down to wiring.

Do you have access to the manual for your boiler. If you do you will find there are two sets of electrical connections, one for the (permanent) 220 volt supply, and the other for the 'external controls'. When you purchase the boiler it will have a link fitted where the external control connections are, you remove this and fit your external controls.

I assume your mechanical timer is fitted to this set of connections. So you remove it a fit a new set of controls.

If you use a wireless system then there are two components, the base unit which will be connected to the aforementioned 'link', and a separate thermostat which is mounted wherever you want to control the temp.

You could keep your mechanical timer and just use a wireless stat. Or you could remove it and use a wireless programmable stat (i.e. one that has a timer AND thermostat function)>

OB1CAN

That's the ticket YOUTHEMAN ..

That's exactly the info I need ... Thank you very much...

I'll let you know when I have it fitted.

Regards

OB

neeb

Just got the zoned job done and its great.