Glow worm Ultracom 30sxi.......no heat to radiators!!!

[Hoody155]

Out of the 8 rads, the only 1 that gets reasonably hot is the 1 in the hallway, 2/3 of the others get luke warm but not hot.....the rest just stay cold. This happens if we have both the HW and CH on or just the CH. The boiler does stop and start, ive noticed it gets up to about 75c on the display but then drops back down to about 35c and then will start to go up again......this seems to happen all the time the CH is on.

I will post a list of all the sizes of the rads and look at the values you mentioned when I get home.

 

[D_Hailsham]

The boiler does stop and start, ive noticed it gets up to about 75c on the display but then drops back down to about 35c and then will start to go up again......this seems to happen all the time the CH is on.

This is probably because the boiler is considerably oversized.

I will post a list of all the sizes of the rads and look at the values you mentioned when I get home.

This info will help confirm if the boiler is oversized. Fortunately, the output of the boiler can easily be reduced.

 

[ScottishGasMan]

regardless of the boiler being oversized, it would certainly sound like there is a circulation issue, if the only issue was a boiler set to high and cycling then all rads would be equally hot or cool, but you say one is warm and some are not heating at all, and the Hot water heats fine? I think you will be looking at blocked pipes more than likley, but without draining the system/checking water quality/turning rads on-off/checking TRVs its very hard to tell.

the pipes feeding the radiators that dont heat, are they all 15mm even at the radiators or are some possibly microbore? are you aware of any plastic central heating pipes to the radiators?

as said, a pic of the pipework and set up under the boiler/valves ect would be handy incase theres by chance something simple like an open bypass etc

 

[ScottishGasMan]

sorry just seen pics of boiler there,

 

[Hoody155]

Here is a list of the radiators, there are actually 9 not 8 as 1st stated...
Lounge - 1910mm x 580mm – single panel
Lounge2 – 1750mm x 740mm – single panel
Hallway – 1440mm x 600mm – single panel
Bedroom1 – 1600mm x 600mm – single panel
Bedroom2 – 1590mm x 600mm – double panel
Bedroom3 – 1920mm x 600mm – single panel
Bedroom4 – 1760mm x 600mm – single panel
Bathroom – 960mm x 600mm – double panel
Landing – 960mm x 590mm – single panel

These are the values when the CH is 1st turned on....
d.40 - 46
d.41 - 31

 

[ScottishGasMan]

can you get the D40/41 values just before the heating shuts off again?

 

[Hoody155]

when you say 'shuts off', do you mean when we turn the CH off? Excuse my complete lack of knowledge!!

 

[matt1e]

when you say 'shuts off', do you mean when we turn the CH off? Excuse my complete lack of knowledge!!

no he means when the boiler cycles off on its own

 

[ScottishGasMan]

Yep exactly, need to see the D40/41 flow and return temps as the boiler turns its self off, that way we can gauge the circulation through it

 

[Hoody155]

Do you mean when the ch reaches the set temperature and then turns off? If so, because the heating isnt working it doesnt ever get to the point of reaching the temperature and therefore doesnt turn off, if that makes sense? Thanks

 

[ScottishGasMan]

I dont mean the heating going off as in the room thermostat turning off because the house is warm.

I mean the D40/41 as the flame turns off on the boiler because the boiler has reached temperature as it cycles on and off.

 

[Hoody155]

Sorry to ask so many questions but how will i know when the boiler shuts off and how often does it happen? Thanks

 

[Agile]

You need to watch or listen to the boiler.

Or to be a little easy for you just take them when the boiler has been firing for a few minutes.

Tony

 

[Hoody155]

I have made a note of the values at the start, after 5mins, 10mins and 20mins of the CH being on. After about 5/10mins of the boiler being on, a fault code showed....F25, i reset the boiler, the fault hasnt showed again (yet)......

Start –
d.40 – 24
d.41 – 18
5mins –
d.40 – 52
d.41 – 33
10mins –
d.40 – 48
d.41 – 41
20mins –
d.40 – 75
d.41 – 42

I noticed the d.40 value will shoot up to about 75 and then shoot back down to about 42, this happens over and over again

 

[D_Hailsham]

Here is a list of the radiators, there are actually 9 not 8 as 1st stated

Thanks for the list. From the dimensions, they would appear to be old imperial sized rads (inches).

You haven't said if any of the rads have fins on the back of the panels. This makes a noticeable difference to the rad output

You can get:

One panel - no fins
One panel with fins
Two panels -fins on one panel
Two panes - fins on both panels.