Central Heating controls

Bruthal

Sir Arthur Daley wrote: »

Good idea, oil boilers can trip out the high limit especially if the thermostat is turned up high.

Yea that's the main problem with no over-run alright.

Sir Arthur Daley

Bruthal wrote: »

If I'm reading correctly what the op is trying to do, then the HW channel can bring on the pump and boiler.

The CH channel can bring on a DP relay.

Connect zone valves to one pole. And other pole can switch in parallel with HW channel.

So HW switches only pump and boiler. CH brings all on. I think that's what OP was asking for.

Just getting back to this configuration, that is a nice simple way of giving hw only or hw and ch. It may be possible to set the clock up to give hw if ch is selected like in the conventional analogue grasslan or flash ones.

Bruthal

Sir Arthur Daley wrote: »

Just getting back to this configuration, that is a nice simple way of giving hw only or hw and ch. It may be possible to set the clock up to give hw if ch is selected like in the conventional analogue grasslan or flash ones.

With the relay used, it will give either HW alone, or CH and HW.

All assuming we are seeing correctly what was being described:)

Sir Arthur Daley

Bruthal wrote: »

With the relay used, it will give either HW alone, or CH and HW.

All assuming we are seeing correctly what was being described:)

Yea on the ball, i guess a 3 channel clock is the way to go to get the benefits of the zones. If he wants to keep the 2 channel my suggestion in post 21 would be a way of gaining seperate heating zones. I know if he switches on the other ch the hw wont come on but one could put in relays and configure to achieve seperate ch and have hw come on with each and in the summer just turn down the room stats.

Bruthal

I don't think the op has access to separate zones for upstairs and downstairs. Think he said he thinks a single switch wire leaves timer and splits to 2 stats and valves.

The 3 items he can switch are pump, boiler, and valves for radiators from what I can see. So a 3 channel time clock won't work properly either if that's the case.

I could be seeing it wrong though. Don't seem to be seeing too clearly lately.

Sir Arthur Daley

Bruthal wrote: »

I don't think the op has access to separate zones for upstairs and downstairs. Think he said he thinks a single switch wire leaves timer and splits to 2 stats and valves.

In post 11 he says he has 3 valves, 2 for ch and one for hw.

Bruthal

Sir Arthur Daley wrote: »

In post 11 he says he has 3 valves, 2 for ch and one for hw.

He has the valves, but has he got the switch wires?

Sir Arthur Daley

Bruthal wrote: »

He has the valves, but has he got the switch wires?

Good point, he needs to tell us what he has at the clock.

If its plumbed for 3 zones surely it was wired sufficiently to accommodate it.

n0brain3r

2011 wrote: »

This will do it for you.
However it requires a 3 channel time clock as Sir Arthur Daley suggested.

That would be my ideal setup but I don't think I have enough wires at the timer only 1 for boiler, 1 for the circulating pump and 1 that powers the circuit with the room stats and zone valves on it.

Bruthal wrote: »

If I'm reading correctly what the op is trying to do, then the HW channel can bring on the pump and boiler.

The CH channel can bring on a DP relay.

Connect zone valves to one pole. And other pole can switch in parallel with HW channel.

So HW switches only pump and boiler. CH brings all on. I think that's what OP was asking for.

But if there are 3 motorised valves, the one for HW has to come on with HW channel once it's stat is closed.

Anyway, relays can be used to keep different items isolated from each other with reference to exactly what's needed.

Thats it exactly 2 mororised valves one for upstairs and one for downstair the cylinder/HW is a TRV like on a radiator.

Bruthal wrote: »

He could. I actually drew it out just like that. But a relay is how I'd do it. Keeps it simpler to operate.

But I'm not completely clear on the setup. Are the valves simply being used as valves?

Are their contacts being used?

A pipe stat giving pump over run might be good as well. Might be OK without it on oil boiler though.

I think just valves there's 4 wires in each valve but only 2 used on each.

Bruthal wrote: »

I don't think the op has access to separate zones for upstairs and downstairs. Think he said he thinks a single switch wire leaves timer and splits to 2 stats and valves.

The 3 items he can switch are pump, boiler, and valves for radiators from what I can see. So a 3 channel time clock won't work properly either if that's the case.

I could be seeing it wrong though. Don't seem to be seeing too clearly lately.

That's it exactly

Bruthal wrote: »

He has the valves, but has he got the switch wires?

I don't think so

Sir Arthur Daley wrote: »

Good point, he needs to tell us what he has at the clock.

5 wires neutral, live, live to boiler, live to circulating pump and a single live to the 2 valves and stats I'm guessing it must split somewhere to serve each.

Its a gas boiler too btw

thanks for all the replies!

Sir Arthur Daley

Is there a big joint box in hotpress where mv are?

n0brain3r

Yes I think this is where the live from the clock is distributed to the stats which feed back to the mv

Sir Arthur Daley

n0brain3r wrote: »

Yes I think this is where the live from the clock is distributed to the stats which feed back to the mv

Can you open it and put up pics along with clock wires and boiler, interested in seeing it.

n0brain3r

Sure will grab some pics in the morning thanks for bearing with me!

Bruthal

Why do you think one of the switched wires is to the pump? Is it not a system boiler with pump, pressure gauge, expansion vessel etc all built into it?
Is the timer beside the boiler?

Are there 3 motorised valves in the hot press?

My own house is not done properly either. Only one valve in hot press to do all radiators. And it does not turn them off. Probably not closing propely. I keep meaning to put in a hand valve to test, then replace motorised valve.

n0brain3r

Bruthal wrote: »

Why do you think one of the switched wires is to the pump? Is it not a system boiler with pump, pressure gauge, expansion vessel etc all built into it?
Is the timer beside the boiler?

Are there 3 motorised valves in the hot press?

My own house is not done properly either. Only one valve in hot press to do all radiators. And it does not turn them off. Probably not closing propely. I keep meaning to put in a hand valve to test, then replace motorised valve.

I was wrong on having the pump I drew it out like that when trying to figure out how to wire the system for more control but it's a single wire to the boiler and pump.

Timer is beneath the boiler.

I've attached PICs of the wiring an valve layout I've only got motorized valves for up and downstairs the cylinder is a TRV type valve based on the temp of the cylinder.

frankmul

How does a boiler interlock work with that cylinder trv?

K.Flyer

frankmul wrote: »

How does a boiler interlock work with that cylinder trv?

It doesn't, and there is no sign of any automatic by-pass either.

Rip it out and start again:eek: wire it as a S-plan with a 3 channel programmer (as mentioned), whatever it costs it will cheaper than the repair costs that will be needed down the road and you would then have a boiler with interlocks helping reduce fuel costs and it would just be right.

Wiring for gas boilers is regimented, it starts with the boilers specific requirements all day every day, the requirements can differ from boiler to boiler but is usually a variation of a S plan, Y plan or W plan depending on the plumbing configuration, always follow the boilers MI and not the wiring instructions that come with the external control packs.

With bad heating system design the wiring is very important as bad wiring can exacerbate any problems with the installation. To wire other than the specific boiler requirements commonly leads to blown pcb boards, boiler safety devices bypassed(at times), power coming on to the boiler after local electrical isolation.

Systems like this should really be a thing of the past as they damage the boilers longevity, lead to higher fuel costs and the sparks can get reported for wiring a gas boiler not to current standards.

Also with a added external pump overrun and domestic gas boilers, it's not needed if it was the boiler would be dealing with it or the MI would be specifying it , if you find yourselves looking at this as a option then your usually dealing with symptoms of a problem and not the problem.

n0brain3r

K.Flyer wrote: »

It doesn't, and there is no sign of any automatic by-pass either.

Should I be worried an interlock would stop the boiler firing if no zone called for heat and the timer switched the boiler on right? Whats an automatic bypass? The manual says it has one internally will this do? It's an Ideal Mini S24 manual is here http://idealboilers.com/installer/wp-content/uploads/sites/2/2013/08/mini_is32.pdf

gary71 wrote: »

Rip it out and start again:eek: wire it as a S-plan with a 3 channel programmer (as mentioned), whatever it costs it will cheaper than the repair costs that will be needed down the road and you would then have a boiler with interlocks helping reduce fuel costs and it would just be right.

Wiring for gas boilers is regimented, it starts with the boilers specific requirements all day every day, the requirements can differ from boiler to boiler but is usually a variation of a S plan, Y plan or W plan depending on the plumbing configuration, always follow the boilers MI and not the wiring instructions that come with the external control packs.

Do you mean replace just the clock or everything zone valves and rewiring etc.?

I think the wiring that applys to my setup is on pg. 24 of the pdf linked above all I did was replace a failed analogue single channel clock so I don't think it was ever wired properly?

gary71 wrote: »

With bad heating system design the wiring is very important as bad wiring can exacerbate any problems with the installation. To wire other than the specific boiler requirements commonly leads to blown pcb boards, boiler safety devices bypassed(at times), power coming on to the boiler after local electrical isolation.

Systems like this should really be a thing of the past as they damage the boilers longevity, lead to higher fuel costs and the sparks can get reported for wiring a gas boiler not to current standards.

Also with a added external pump overrun and domestic gas boilers, it's not needed if it was the boiler would be dealing with it or the MI would be specifying it , if you find yourselves looking at this as a option then your usually dealing with symptoms of a problem and not the problem.

It was installed in 2008 would it of been the norm then? I just checked with the neighbour and his is identically wired. What would added external pump do (I may have confused things I'm not looking to add one) and whats an MI ?

n0brain3r

n0brain3r wrote: »

Should I be worried an interlock would stop the boiler firing if no zone called for heat and the timer switched the boiler on right? Whats an automatic bypass? The manual says it has one internally will this do? It's an Ideal Mini S24 manual is here http://idealboilers.com/installer/wp-content/uploads/sites/2/2013/08/mini_is32.pdf

Never use a inbuilt boiler bypass as a system bypass(even if the MI asks for it) as they block very easily with dirty systems, good working practise and system longevity requires a auto bypass to be fitted external to the boiler.

n0brain3r wrote: »

Do you mean replace just the clock or everything zone valves and rewiring etc.?

I think the wiring that applys to my setup is on pg. 24 of the pdf linked above all I did was replace a failed analogue single channel clock so I don't think it was ever wired properly?

I mean take out all the wires, buy a 3 channel programmer and correctly connect all the components you have as a S plan with the H/W channel firing the boiler direct.

The diagramed shows a mid position valve which is the most common type of installation in the UK your more interested in a S plan.

I'd think about a frost stat as well if one isn't fitted.

n0brain3r wrote: »

It was installed in 2008 would it of been the norm then? I just checked with the neighbour and his is identically wired. What would added external pump do (I may have confused things I'm not looking to add one) and whats an MI ?

Strangely enough "what's MI?" is a question I get most weeks from sparks, it means manufactures instructions:D

It was never the norm, gas boiler wiring is regimented and hasn't really changed in over forty years, you wire this as a S plan utilising the switching of the M/Vs.

Forget about the pump overrun, I was just responding to a suggestion you may want to add it, you don't.

Sir Arthur Daley

Wiring using the S plan is still not the right thing to do here if there is no external bypass. We are back to the scenario of where a system is plumbed incorrectly. Is it as simple as installing a bypass to get this system plumbed correctly?
I would suggest get rid of the TRV off the HW coil, install a TMV (blending valve) and put a 3 channel clock on the system. I see nothing wrong with having HW on demand either and the op could use his 2 channel clock to control his 2 heating zones with, just my 0.02.

Sir Arthur Daley

Sir Arthur Daley wrote: »

Wiring using the S plan is still not the right thing to do here if there is no external bypass. We are back to the scenario of where a system is plumbed incorrectly. Is it as simple as installing a bypass to get this system plumbed correctly?
I would suggest get rid of the TRV off the HW coil, install a TMV (blending valve) and put a 3 channel clock on the system. I see nothing wrong with having HW on demand either and the op could use his 2 channel clock to control his 2 heating zones with, just my 0.02.

Your right, it should be wired as a S-plan with a auto bypass.

The auto bypass is very inexpensive and simplistic to fit.

Dtp1979

I'm sorry. I'm confused. Did a sparks and a gas fitter/plumber just agree on something??

Dtp1979

Dtp1979 wrote: »

I'm sorry. I'm confused. Did a sparks and a gas fitter/plumber just agree on something??

Err... I'm on their site and they can be really grumpy about heating wiring, so I'm trying a few things I just learnt at couples counciling;)

Sir Arthur Daley

Just to throw a query out, the boiler has its own bypass and the manufactures surely believe this suffice so is one going against the boilers manufactures instructions fitting one?

Sir Arthur Daley

Sir Arthur Daley wrote: »

Just to throw a query out, the boiler has its own bypass and the manufactures surely believe this suffice so is one going against the boilers manufactures instructions fitting one?

All manufactures will tell you that but in reality the boiler bypass isn't very good as a system bypass, without a auto bypass on the system you risk boiler pumps burning out, underfloor not working very well, and over heating issues, the pump and over heat issues tend to show themselves a few years down the road and are costly as the original issuess are rarely identified or put right.

It's good working practise to fit a auto bypass.

n0brain3r

Where would the best place to fit the bypass be? I think I could manage to fit one between the cylinder flow and return would this suffice?

To rewire to S plan what sort of wire should I use?

And I thought I might get out of this by buying a couple of relays!

Sir Arthur Daley

I would get a plumber to look over the installation op, get it piped right first anyway.

frankmul

How does this tie in with part L building regulations?

2011

frankmul wrote: »

How does this tie in with part L building regulations?

My understanding was that Part L was for "Conservation of Fuel and Energy - Buildings other than Dwellings" and as such would not apply.

Link

Perhaps I am missing something ?