Central Heating problem

D

doresy

Hi all, first post here so hope it conforms! :)

My System. Boiler- old Potterton Netaheat 10-16. Pump, newly fitted Grunfoss. Programmer Danfoss.

Heating is pumped and hot water gravity fed.

Ok, after the summer I ran the central heating for the first time and realised that the pump was seized as it was buzzing but no rads were getting hot.
As the shut off valves were totally corroded I employed someone who drained the system and fitted a new Grundfoss pump and 2 new valves.

The problem I have is the pump is live (running) if the room temperature drops below thermostat setting even if the programmer timer is off. The boiler only comes on as well during the timer on period.

I decided to replace the programmer too (like for like) and it seemed to work fine, then later all the rads got hot even though it was set to hot water only. I then discovered the pump was running continuously again, stopping only if I turned the thermostat down to zero.

Any thoughts please???
 
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Well, if you have a gravity fed HW system you shouldn't have a 3 port valve anyway (it's used in a fully pumped system to switch the hot water from the boiler between the heating the HW tank and the CH)

It would look something like this

http://www.plumbworld.co.uk/honeywell-v4073a-3-port-763-1367

Though you may have a 2 port version of it on the system.


My first thought is that there might be a wiring error. I say this as I managed to wire mine up recently to behave rather like yours when I completed some modifications to the system :oops:

There are wiring diagrams of typical setups around if you are able to interpret them to check yours.
 
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ctp

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Electrical fault, clock powers boiler on hot water and heating, on hot water only clock only powers boiler and the hot water runs on gravity. On h/w +htg the clock powers the pump via the roomstat. On old gravity systems you cannot run the htg separately from the hot water.
 
D

doresy

Well, if you have a gravity fed HW system you shouldn't have a 3 port valve anyway (it's used in a fully pumped system to switch the hot water from the boiler between the heating the HW tank and the CH)

It would look something like this

http://www.plumbworld.co.uk/honeywell-v4073a-3-port-763-1367

Though you may have a 2 port version of it on the system.


My first thought is that there might be a wiring error. I say this as I managed to wire mine up recently to behave rather like yours when I completed some modifications to the system :oops:

There are wiring diagrams of typical setups around if you are able to interpret them to check yours.

Thanks for that. I didn't think there was a need for a 3 way port valve and as I cannot see any valve whatsoever I guess that's not the answer.
When the new pump was fitted it was a simple task of de-wiring the old one and hooking up the new one so an error here would just mean the pump wouldn't work I guess?
As no wiring has been altered I cannot see why the pump is getting power even when the timer is in an off setting
 
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"Grundfos" should only have just ONE "s" !

Exactly which pump model is it?

Are you on Facebook?

Tony
 
D

doresy

"Grundfos" should only have just ONE "s" !

Exactly which pump model is it?

Are you on Facebook?

Tony

Ok, Grundfos :D

The model no. is UPS2 15-50/60


(will check back with you tomorrow, ta) (Ps, Facebook?- yes)
 

ctp

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Is the pump wired directly to the boiler via a pump overun some 10.16s had this option fitted.
 
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Look for my posting on the Grundfos page on Facebook!
 

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