Glow Worm Combi 100e warm radiators

[PaulcStead]

Hi, my radiators are only getting warm but hot water is ok. If i close off most of the radiators the ones left open are getting very hot. Read a few threads about the boiler pipes getting warm etc, but if all the radiators are open the pipes are warm.
Also, if i turn the boiler off a few times the heat does start to come through. Could the pump be on its way out?

 

[Gasguru]

We talking about the Compact 100e?
Maybe a blocked return filter..if DHW is fine then the pump is probably ok too.

 

[PaulcStead]

Hi yes it’s the Compact 100e. Would that explain If i isolate radiators the others are hot?

 

[Gasguru]

Are you sure you don't have a radiator balancing problem...do the radiators all heat up at a similar rate?

If the filters's blocked then the boiler will struggle to get the heat out.
There are other possibilities but only a thorough check would confirm...not easy on a forum.
A weak pump would often show as poor hot water performance/overheating etc.
When turning the boiler on/off the radiators heat up? Are you just giving it more time to heat up or is there a noticable difference when the boiler power is cycled?

 

[PaulcStead]

I have part closed the rads upstairs to try and push heat downstairs. Most warm up at a similar rate yes.
Difficult one to answer as this seems to be different sometimes. It’s almost as though the heat pulses through hot then warm. If the heating has been on for a full day then back on the next day, the rads can get hot.

 

[Gasguru]

Might still be worth pulling out the return filter located in the base of the pump connection (accessed from below the boiler AFAIR).

 

[PaulcStead]

Thanks Gasguru, assume this would require a boiler drain?

 

[Gasguru]

Yes a boiler drain down, bleed the rads and if there's a sufficient upstand of pipework into the boiler you should be able to leave the system fill of water.
Have fun re-charging the vessel...a right angled tyre valve extension comes in handy.

 

[PaulcStead]

Excellent, thanks for the advice... ill try tomorrow.

 

[PaulcStead]

Morning, ok so the boiler has been drained, filter removed and cleaned. Re charged the vessel, heating on so let’s see what happens.

 

[PaulcStead]

Update. All the rads are now boiling hot!!!! Can’t thank you enough, you were spot on and only cost me a foot pump for the vessel.

 

[PaulcStead]

Hi Gasguru, sadly the problem hasn't gone away. I've cleaned the filter again, did a complete full system drain and now running with Sentinel X400 since Saturday. Rads still warm and sometimes the water isn't 100% as it used to be. Could this be the pump or controller board? How could i diagnose either?

 

[Gasguru]

Turn the DHW temp to max and gas rate the boiler...see the FAQs.
A common issue on these is failure of the burner to ramp up to maximum output.
The pcbs are NOT plug and play...requires Gas-safe installer to replace.
Other than that the plate heat exchangers are very sensitive to debris...only proper cleaning will restore them.
Or the diverter is sticking, or the pump is weak etc etc.

Terrible boilers..

 

[PaulcStead]

When you say "A common issue on these is failure of the burner to ramp up to maximum output", is this down to the controller pcb?

 

[Gasguru]

Yes