2 months with CH issues

[fohnot]

Hello, I'm hoping I can get some advice as I've had a bit of a saga with my central heating over the last couple of months. Here's a potted timeline:
GlowWorm boiler installed in 2015
Early August 2023 boiler not working - Boiler screen showing F23
Engineer reset and did various tests
Boiler stopped again shortly after he left, advised to keep resetting
After 2 weeks with same fault showing engineer said could be pump or sludge
Reset again and asked us to record pump speeds which we did
Early September and engineer thinks definitely pump and valve problem plus chemical flush required
mid-September and they finally turned up to add chemicals - system pretty much works well after this
A few days later they turn up to replace pump and valve and to flush system (we think he did two flushes)
Rads upstairs heating but no heat in downstairs rads. Engineer thinks blockage somewhere but doesn’t know where.
A week later and they're back - they play around but still upstairs rads heating but no heat downstairs . After they left I found a thermostatic valve top lying on bathroom floor
Next day heating is working and stays working except for a couple of rads. Tried bleeding them but they do have water to the top.
Another week later and engineer comes back and said the blockage was in the return pipe at the boiler and if they did a flush it may leak. Pipe should be replaced from boiler to upstairs airing cupboard. Two day job with disruption to stair and landing carpet.

Obviously there were frustrating huge elapsed time gaps but I'm getting nervous. Do you think I'm being taken for a ride / is their engineer out of their depth and just guessing? Or does it sound correct that the pipe needs to be replaced?

Thanks so much in advance for anyone's advice!

Dave

 

[Johntheo5]

Is it a system, heat only or combi boiler?, if a combi, is the hot water output and temperature OK, if either of the other two, do you get a F23 when heating the HW cylinder?

 

[fohnot]

Hi John, thanks for your message. Not a combi. HW heating has been consistently fine.

Thanks

 

[Johntheo5]

Your engineer said (return pipe) should be replaced from boiler to airing cupboard, does this pipe also feed the HW cylinder coil, either to a S system with separate zone valves or is it a Y system with a mid position valve?

 

[fohnot]

Hmmn my knowledge isn't up to answering that. Does this photo help?

 

[CBW]

S - plan system

 

[Johntheo5]

What is the make/model of the boiler?
Have you separate zone valves for upstairs/downstairs heating? I can see two motorized valves in your photo, one of which is for the HW cylinder coil to control the HW temperature.
There is a automatic bypass valve located a little further down from the circ pump can you see what setting this is on, it should show a setting between say 3.0 to 4.5
When the pump is running can you take a photo of the LEDs, also pump model.it looks to be orientatd correctly pumping downwards as they didn't bother to swing the head around, check that arrow on the pump body is pointing downwards just to be sure.

 

[fohnot]

Hi so sorry for the delay I was away from the house. It's a Gloworm Energy 18R. I've attached a couple of pics of the pump LEDs

.

 

[Johntheo5]

That pump is on Speed2 which should provide plenty of flow as it it will pump up to 28LPM at a 5.2M head.

There is a automatic bypass valve located a little further down from (below) the circ pump can you see what setting this is on, it should show a setting between say 3.0 to 4.5

 

[fohnot]

I'm assuming that's what you meant?

 

[Johntheo5]

Thats it, can you post its setting or a close up photo.

 

[CBW]

Thats it, can you post its setting or a close up photo.

0.2 by the looks of it.

 

[Johntheo5]

Yes it is! should have selected it and its clearly seen.

Would suggest to OP that he keepks turning it clockwise (lots of turns) until it reads 0.45, its probably recirculating anything up to 18LPM at that 0.2 setting, a setting of 0.45 with a pump head of > 5M should recirc ~ 5 to 6LPM and should help to circulate the water through the rads.

 

[fohnot]

Ok thanks. Let's see how we go!

 

[fohnot]

The cold morning this morning helped make a judgement on the change. I set it to 0.45 and there is now a toasty hot first radiator downstairs on the system but the next two are only lukewarm after 3 hours of running while the final is cold (this one has always been somewhat poor).

Would appreciate further thoughts!

Thanks