We have a twin zone system (seperate ground and first floor heating) the 1st floor will heat up to 20c+ with no problem, but the ground floor will not go over 15c??

The room stat on the ground floor is OK.

The motorised valve for the ground floor opens/closes OK

Boiler was replaced last week and this is the first time of trying the heating!

Could it be wired up wrong and is tripping the boiler out?

It was all working OK with the old boiler.

Please help as the Corgi guy is denying all responsibility

The thermostat performs several things on a zone system when it calls for heat. Opening the zone valve is not enough. It must also send a signal to the boiler to fire up and start the pump. There should be a wire from each thermostat or zone valve to fire the boiler and start the pump. If the boiler and pump are running when the ground floor thermostat is calling for heat and the first floor isn't, likely the one wire was disconnected. I would call the guy back and ask why the boiler and/or pump don't start when the ground floor thermostat calls for heat.

It might be more quick to spot a disconnected white wire and connect it to the terminal where the other white wire is connected.

Many thanks for your reply, the ground floor thermostat does call for heat, and it has no problem heating up to 15c, after that point it will not call again?? I swapped the ground and first floor stats around in case the stat was faulty but no difference!

Sitting in a house now a bit cold :(

When you are not getting the heat called for, is the boiler and pump on, and the zone valve open? Is it very consistent about the temperature? I was seeing the problem as it continuing to call for heat, but not getting any after the other one allowed the boiler to shut off. This sounds more like some malfunctioning limit switch. Compare the wiring for both thermostats. Usually the white wire is hot when calling for heat. They should both have all the same connections at the boiler and pump, but differ only on which zone valve they are connected. The zone valves should be wired alike, except for the wire from the thermostat.

So who is the Corgi guy? Is he/they the installers? The installer just installed the heating system and does not have any responsibility to install a system that actually works? Have you paid for the job completely? Is there a consumer protection agency that will force this installer to make good on his work?

If the system is wired properly, judging from the tests you have observed, it is, sounds as if the hot water loop you are not getting heat from is air bound. A pocket of air is in the piping loop somewhere and is preventing the hot water to flow. The system may need to be flushed to force tha air out.

This is a simple procedure, I have done it myself on several heating systems for friends and relatives, never having owned a hot water system myself.

However I will not be very helpful from hereon, as each system is set up a bit differently, and I will not be able to explain how to do it, I only have been able to look at a system and figure out how to do each one as I go.

Basically, a valve needs to be closed to prevent the normal water flow from the boiler out to the loop. Find a location on the boiler to connect a garden hose,then the input water valve is opened, hthis will force fresh water through the system and the air will be forced out.

I am sure there are more helpful details to be given, however this is the best I can offer. Perhaps some pictures of your system, and someone like an expert such as speedball, that has plumbing experience, can help you further.

I do think you need to force the installer to remedy this for you, without cost. Did he ever hear of a warranty? I get from the celsius measurement that you are either in Canada, UK or somewhere other than the USA. Here in the USA, all licensed installers of mechanical equipment must warranty their work for one year. And if we don't, there is several gov't agencys that will force us to, and can jepordize our licenses.

Hope this helps some.

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Originally Posted by labman

When you are not getting the heat called for, is the boiler and pump on, and the zone valve open?

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No, the boiler/pump is off and the zone valve is closed!

When I put the heating on first thing, set downstairs stat to 20c (room temp then say 10c) the boiler will fire up continusly until it reaches 15c then it will not come on again for about 1/2 hour and only run for about 5 minitues then off for another 1/2 hour, it seems to only want to keep the temp up to 15c while room stat set at 20c!

Upstairs will heat up to 20c+ with no problem

The installer is denying all liability, saying it's the original system (which was fine before!)

I would thank you for your help so far.

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Originally Posted by tkrussell

I do think you need to force the installer to remedy this for you, without cost. Did he ever hear of a warranty? I get from the celsius measurement that you are either in Canada, UK or somewhere other than the USA. Here in the USA, all licensed installers of mechanical equipment must warranty their work for one year. And if we don't, there is several gov't agencys that will force us to, and can jepordize our licenses.

Hope this helps some.

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In the UK, the installer replaced the boiler only, system 19 years old.

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Originally Posted by mike 25

In the UK, the installer replaced the boiler only, system 19 years old.

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Part of installing the new boiler includes connecting the existing wiring to make it run. It should also include filling the system with water.

Mentioning Speedball reminds me of plumbing problems. Replacing the boiler may have knocked loose some crud that found its way out into the old system. There, it could be messing up some safety switch. Your description sounds much like a forced air system with a bad limit switch. Follow the plumbing from where it tees off to the zone valve clear around the loop. Look for some wires connected to a fitting on the pipe.

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Originally Posted by labman

Your description sounds much like a forced air system with a bad limit switch.

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Are you talking about the room stat or something else? if so where would I find the "limit switch", as I think you may be on to the solution here

Also "forced air system" are you saying there is air in the system, what do I connect to, to be able to flush air out ?

Once again many thanks. :) :)

When I said forced air, I was referring to a conventional system. They have a switch inside the furnace that shuts the gas off if it get too hot. It sounds to me like your system has a switch somewhere shutting it down because of a problem or bad reading. I don't know where such a switch might be. That is why I said check the whole system looking for a fitting with wires going to it.

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Originally Posted by mike 25

No, the boiler/pump is off and the zone valve is closed!

when I put the heating on first thing, set downstairs stat to 20c (room temp then say 10c) the boiler will fire up continusly until it reaches 15c then it will not come on again for about 1/2 hour and only run for about 5 minitues then off for another 1/2 hour, it seems to only want to keep the temp up to 15c while room stat set at 20c!

Upstairs will heat up to 20c+ with no problem

the installer is denying all liability, saying it's the origional system (which was fine before!)

I would thank you for your help so far.

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does each zone have its own balancing valve ( isolation valve)* manual one... the hi temp limit will shut off the boiler when water temp too high...

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Originally Posted by caibuadday

does each zone have its own balancing valve ( isolation valve)* manual one... the hi temp limit will shut off the boiler when water temp too high.....

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if your sysem was working fine before... these are what I would check... make sure no air in the system ( did He bleed out the air after fill up?)... make sure all valves (watervalve) are open( or balance- so it would give the zone enoght flow but won't reduce /increase the flow of another zone)*count and remember how many you turnt...