no heating

[opps]

hi all.

i recently removed a rad that was not getting hot and decided to flush it out. After replacing it I discovered that now only one rad near to the boiler is getting hot.

when i call for water the boiler (poterton profile) fires up for a minute or two and then shuts down. to get it up again i have to turn up the thermostat on the boiler (i have only tried this for a couple of minutes). sounds like th pumps continues to run even though the boiler goes out.

have checked that room stat is ok.

the pump sounds like it is working. i did loosen the screw on it very slightly and it dripped water.

i had checked previously that the header tank is working.

have i ended up creating a blockage, the onlt rad that gets hot seems to do so by radiation

thanks in advance

 

[gas4you]

Remove your pump and check it is working properly, maybe flush it through as well. It sounds like your whole system needs a thorough cleaning.

The pump could be spinning but not circulating the water, or you have a more serious blockage or air lock

 

[opps]

thanks Dave

if it is an airlock how do i flush it out??? and does the pump push or pull the water???

do you think this is definately my fault or more a case of a clogged system getting worse because of my actions or other???

i ask because it's my friends house and i would like to know how culpable i am.

btw between the pump and the cylender there is a fork with a stopcock which runs of at 15mm. anty ideas what this is???

thanks

 

[gas4you]

From what you have said I think it is just an unfortunate occurrence in circumstances. Just removing one radiator should not cause further problems.

The 15mm branch with gate valve is probably a system bypass, so the pump has always got a path to pump through.

I keep saying pump, but in fact the pump is not a pump in the true sense of the word, but a circulator.

It could be pushing if it is in the flow from the boiler, or pulling if in the return. It sounds like it is pushing from your description. There will be an arrow in the pump casting pointing to its direction.

Try shutting the bypass, put pump on max speed, turn hw off, turn ch on, turn off all rads except one and see if this will push water through.

Banging you mention and boiler going off is due to no circulation.

The rad getting hot would'nt be the bathroom one would it?

 

[opps]

hi Dave

err the rad getting hot is the bathroom one how did you know that.

ordinarilly should the bypass be open or closed and where does it go to

thanks again for your help thus far

 

[gas4you]

Could be an old system where the bathroom rad is piped off the gravity primarys to the hw cylinder, in which case this would get hot whenever the hw is on and doesn't rely on the pump.

If the gate valve is a bypass then once you get the system working when it is shut, just open it about 1 to 1 1/2 turns

 

[opps]

ahhh... i see.

am following yor advice at the moment.

given the size of the house i fear it might take some time though.

 

[JohnD]

You say "I had checked previously that the header tank is working."

Could you tell me how you checked please?

 

[ChrisR]

Pumps don't really suck or push , they develop a pressure between the ends...
When you disturb an old system they're often reluctant go as well as before. Air in the pipes is often the reason, but pumps can be only-just working and you may hardly notice it. They lose torque over time, and block up if the system's dirty.
This pump was taken out because its bearings were knackered,

whereas this one wasn't very old, was spinning at full speed, quietly, doing very little

 

[opps]

thank Chris and John

i had checked the header tank to ensure that the ball cock was not stuck. i am assuming that it functions correctly as the water level after filling the rad was at the old tide mark.

a number of years ago i removed a smallish rad and replaced it without noticing that the header's ball cock was stuck... resulting in the pump running dry.

i had noticed that the grunfloss is quite a bit hotter than the water.

should i recommend that the system is power flushed or drained/primed/cleaned etc?

what are the pros and cons for a four story house

thanks

 

[JohnD]

Did you observe if water flows out of the F&E into the radiators? For example, if you drain a bucket of water out of the rads, does an equivalent amount flows out of the F&E?

Blockages are quite common.