boiler change - now upstairs radiators warming up when only

[rickydoo]

old boiler removed from a gravity fed system which incorporated a pump for central heating circulation and a header tank.
New boiler is Echotec Plus and system changed to a closed system incorporating a motorised valve. Every time the boiler is switched on for hotwater the upstairs radiators get warm and then gradually getting more warm and some heat then coming into the radiators downstairs.
Central heating and hot water combined appear to work ok.
Previusly the radiators only came on when required.
Any veiws?

 

[kevplumb]

valve is not closing properly

 

[rickydoo]

valve is not closing properly

Thanks for the response.

I take it that you are refering to the motorised valve not closing properly. It has only been in use for 3 months or so. When hot water is on and heating is off, the hot water pipes get pretty hot, the c/h pipes remains cold but after a while it warms up near to the joint to the valve. Is it that there is a small leak? How can the leak be confirmed?

 

[kevplumb]

could be dirt in the system if it wasn't flushed properly

 

[heytesto]

Has this been a problem from the beginning?

 

[namsag]

with all pipes around boiler being cold stick hot water on and as you start to feel heat coming into rad feel the heating pipe about 12 inches away from the motorised valve if this is cold then a TEE has been put in the wrong place and needs altering.
IF its hot then its the valve passing

 

[heytesto]

Sorry, but I just need to clarify. The system has been converted to fully pumped incorporating a 3 way valve.

If so, there are 2 possibilities:

1. 3 way valve letting by. (should be obvious.)
2. Reverse circulation. Caused by not picking up all the radiators to one common tee in the primary return.

The way to test is to run HW only and note which end of the rads warm up. Then switch on the heating, if the opposite ends warm up then you have reverse circulation.

 

[heytesto]

Beat me to it namsag

 

[rickydoo]

Beat me to it namsag

Thanks for the response.
Not sure whether the motorised valve is leaking.When hot water only has been switched on, the hot water side pipes get very hot. After a short time the pipe coming out of the motoralized valve for central heating gets fairly warm next to the valve.
The upstairs radiators then start getting warm.
Have established that when hot water only is on, the radiators start to warm on one side but when heating is put on the radiaters start getting very hot from the opposite side. This applies to the upstairs radiators only.

The problem only started when the central heating engineer removed the old pottorton boiler and rplaced it with Echo Tec Plus system boiler at a new location. The system still incorporates the old emersion tank.
I believe the old system was a gravity systen incorporating a pump for central heating circulation.
The new system now incorporates a motorised valve with a pump contained within the boiler.
The old system worked perfectly which leads me to believe that the gas engineer has made an error somewhire which I am now trying to locate.
It is also likely that the valve has a small leak.
All help is appreciated

 

[mogget]

This sounds like a case of reverse flow.

All the radiator returns should join together into one, before meeting the DHW return on its way to the boiler.

If this is not done, a pressure gradient across two or more rad returns can cause hot water to flow through the radiators even though the heating is turned off.

The fact that your radiators heat up on the opposite side to normal, when they shouldn't, excludes the valve letting by as a possibility.

 

[namsag]

Get installer back a T is in wrong place

 

[rickydoo]

Get installer back a T is in wrong place

The installer re-visited. He believes there was a fault before. I am sure there were no faults with the system before- the system had been working perfectly well since 1982 even though it did have a boiler change some years ago.
The installer has now informed me that he needs to cut in a non-return valve to stop the reverse flow. He has confirmed the existance of the return flow.
I am not sure. I believe that the pipe work, especially all the new pipe should be checked and the fault located and rectified?
I am not sure whether the non-return valve will solve the problem.

 

[namsag]

Non return valve is not the answer in time they can seize and or block ,i would not accept it

 

[rickydoo]

Non return valve is not the answer in time they can seize and or block ,i would not accept it

Thanks for the help guys.
Fault associated with the new t which was allowing hot water to mix with the cold on the hot water return to the boiler. Non return valve added which seems to have resolved the fault. Engineer insists it was the only way.
We should be decorating soon and I may ask a different engineer to have a look under the floorboards.
Thanks for the help.

 

[mogget]

Engineer insists it was the only way.

Engineer can't be bothered to do it properly.

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Assuming there's no problems like expensive floor in the way of a pipe etc.