Need some advice on programmable thermostats

[jem16]

My current system uses a combi boiler with TRVs fitted to all radiators except one. As the boiler is outside in the garage I have a 7 day programmable timer in the house. The old room stat which was in the hall area is not in use now.

I am considering a programmable room thermsostat. The central heating engineer I talked to about replacing a single radiator with a double radiator didn't see the point in fitting one as the TRVs should control the heat in each room but did say he'd get some prices from wireless programmable thermostats if I really wanted one. I suspect as a plumber he's not really into the electrical side of it. Perhaps it's really an electrician that's needed?

I could see the benefit, especially at spring/autumn where the timer often brings on the boiler where I don't feel it is really necessary - TRVs eventually cut off the heat but there are times the room temp is high enough to keep it off anyway.

I've looked at the Honeywell CM927 which seems ideal. I assume you would put the room unit in the main living room? My current programmer is a Drayton Lifestyle LP711.

Can anyone advise if getting a programmable thermostat is a good way to go? Is the CM927 a good choice?

I'm not electrically minded so would need it installed - would this be an electrician's job rather than a central heating engineer? What happens with the original programmer - does it replace it or work in conjunction with it?

Sorry for all the questions - just want to get it right. Thanks for any help.

 

[gas112]

927 and 921 are very good wireless stats probably the best.
Easy enough to fit . As its a combi you might as well just remove existing clock.
Any heating guy should be able to do it no need for a spark as CH usually confuses them

 

[Whitespirit66]

With the cost of gas high, and probably going to rise in the coming years, a CH system really needs TRVs and a room stat. As you say, the boiler starts when you think its not really necessary.

Your plumber shoould be able to wire a programmable stat in. The manual for the boiler usually tells you where to connect it. If not, a heating engineer would be better than a spark.

If you fit a programmable stat, this takes over the function of your existing programmer, so it needs removing/disconnecting.

Alternatively, you may be able to wire your unused existing stat into the system, and save yourself some money.

 

[liam2308]

Have fitted a cm927 room stat - programmer. Previously did not have a stat.
Connecting was fairly easy. But it seems to take a long time to bring temperature up to target temperature. I have a new boiler grant condensing which is rated at 26-36 kw House 14 year old 1500 Sq.Ft with good insulation and double glazing heated very quickly with old Horstmann 425 Diadem basically an on-of programmer. Hall could heat from 15/16 degrees to 18/19 degrees in approx 45 mins. Now it is taking 2-2 1/2 hours. Stat is calling for heat but the boiler seems to come on for just a few minutes at a time. I thought it would stay on initially for target temperature to be reached before cyling on and off. I have changed the settings to those Honeywell recommended for oil boiler. Any advice please.
PS also now getting knocking sounds from pipes/radiators when the boiler is on - I don't think this has anything to do with new stat possibly the new boiler . I know that plumber with new piping at the boiler has the water now pumping the opposite way. TRVs in all rooms except hall where the stat is.

 

[Goldspoon]

PS also now getting knocking sounds from pipes/radiators when the boiler is on - I don't think this has anything to do with new stat possibly the new boiler . I know that plumber with new piping at the boiler has the water now pumping the opposite way. TRVs in all rooms except hall where the stat is.

Usually means that the TRV's are designed for flow in one direction only. Reversing the flow causes the pipes to bang.

One way TRV's usually have a single arrow on the body (showing correct flow direction). Modern TRV's have two arrows (both ways allowed).

Has your plumber goofed?

 

[jem16]

927 and 921 are very good wireless stats probably the best.

That's good. I'm not sure what one the engineer was going to find out a price for but I think I will ask specifically for that one. I was just not sure about his ability to fit one as he seemed quite against the idea of having one in the first place.

Easy enough to fit . As its a combi you might as well just remove existing clock.

The wiring for the existing one is already in place from the garage into thie house. Could it utilise that wiring or is it likely to be different?

Any heating guy should be able to do it no need for a spark as CH usually confuses them

I did ask an electrician yesterday but he says he doesn't touch CH - too tricky for him!

 

[jem16]

With the cost of gas high, and probably going to rise in the coming years, a CH system really needs TRVs and a room stat. As you say, the boiler starts when you think its not really necessary.

Does the boiler use more gas whilst it's "ticking over" - i.e. the TRVs have shut down the radiators as temperature has been reached but boiler would still fire occasionally to keep water hot - as opposed to the stat turning off the boiler as temp is fine and bringing it back on when temp falls?

Your plumber shoould be able to wire a programmable stat in. The manual for the boiler usually tells you where to connect it. If not, a heating engineer would be better than a spark.

I think it was the engineer saying he would need to get an electrician as the wireless stats need adjusting to make sure it's only controlling your boiler and not everybody else around that concerned me. Surely this is just a matter of choosing an appropriate wireless channel - and how exactly would we know what everybody else has around anyway!

If you fit a programmable stat, this takes over the function of your existing programmer, so it needs removing/disconnecting.

Could the wiring be utilised? Programmer is in house and boiler in garage - does the control unit need to be right next to the boiler or simply wired to it?

Alternatively, you may be able to wire your unused existing stat into the system, and save yourself some money.

The exisiting stat is the old-fashioned turn dial (analogue) - would really want a more exact digital one anyway.

 

[liam2308]

PS also now getting knocking sounds from pipes/radiators when the boiler is on - I don't think this has anything to do with new stat possibly the new boiler . I know that plumber with new piping at the boiler has the water now pumping the opposite way. TRVs in all rooms except hall where the stat is.

Usually means that the TRV's are designed for flow in one direction only. Reversing the flow causes the pipes to bang.

One way TRV's usually have a single arrow on the body (showing correct flow direction). Modern TRV's have two arrows (both ways allowed).

Has your plumber goofed?

Many thanks - I have checked trvs and they do have only one arrow. This must be what is causing my noise. I cannot reverse the pump as the pipe it is on is the outflow pipe coming from the boiler.

 

[Goldspoon]

Plumber just needs to swap flow and return pipes over...

 

[liam2308]

Plumber just needs to swap flow and return pipes over...

These are Westherm valves is it possible to change over the valve inserts only not the actual bodies. I notice that the valves have a nut shaped top brass /copper insert but was wondering that as they are factory fitted it may not be a good idea to take them out. It would save a lot of trouble if the whole valve body did not have to be removed. Also I am not sure if TRV body is identical to the lock shield body - they look the same.
PS The plumber who installed new boiler did not fit any valves. These were on from original installation. The reason they were a lot noisier was because I installed a Honeywell CM927 room stat to work as a programmer as well. But system was heating up very slowly - a lot of creaks from pipes - hence my original question. On the stat I have now enabled optimisation which is now heating the system far quicker. Noise is much reduced . I would like to correct valves but would prefer not to have to remove complete valves. Do they do any damage to the system.

 

[liam2308]

Plumber just needs to swap flow and return pipes over...

These are Westherm valves is it possible to change over the valve inserts only not the actual bodies. I notice that the valves have a nut shaped top brass /copper insert but was wondering that as they are factory fitted it may not be a good idea to take them out. It would save a lot of trouble if the whole valve body did not have to be removed. Also I am not sure if TRV body is identical to the lock shield body - they look the same.
PS The plumber who installed new boiler did not fit any valves. These were on from original installation. The reason they were a lot noisier was because I installed a Honeywell CM927 room stat to work as a programmer as well. But system was heating up very slowly - a lot of creaks from pipes - hence my original question. On the stat I have now enabled optimisation which is now heating the system far quicker. Noise is much reduced . I would like to correct valves but would prefer not to have to remove complete valves. Do they do any damage to the system.

Have now replaced the one way TRVs that were on the returns with 2 way TRVs but I am am still getting a hammering noise from 2 radiators/pipework. If I turn of radiators no noise if I turn them on noise can be heard. When the systen is initially heating up there is no noise but as temperature gets to operating temperature noise starts. The noise seems to come when the boiler is actually firing. Then dies down when the boiler cuts of. My pump runs continually - so it cannot be the pump. Sludge is not an issue as system has been drained 2 times in the last few weeks and it is very clean. Noise is not comming directly from radiator but from pipework going to these particular radiators. But from what I have read - it could be comming from anywhere in the system as the sound is obviously travelling. Noise is like a dull hammering sound and it is very regular every 3-4 seconds almost sounds as if system was pulsating. Could the problem be the pipes maybe not secured under floorboards.!!