Ideal HE 30 Combi - hot water only hot at low flow rate

[grahamrex]

Hi All. Hoping there are some experts out there that can help me again. Trying to keep this old boiler alive and kicking. Don't have high hopes for this question, but folks were super helpful last time.

I have my hot water dial on the boiler turned up to the max. But the water only gets hot at a low flow rate - i.e. when the tap/shower is running at a steady trickle. If I open tap fully it ends up luke warm. I don't have particularly high flow rate - 30s to fill a 4l container.

Anything I can try to resolve? Last time I had a plumber out to service the boiler he said it wasn't worth it. And it was a miracle it was still running, so he'd rather not touch it

Thanks,

Graham

 

[Deleted member 267285]

Could be a few things, including a blocked heat exchanger. Maybe try a different engineer or ideal fixed price repair?

 

[dilalio]

2lpm flow rate!
Is that from a mains cold tap?
Outside tap or washing machine feed is best to test from as they don't have restrictive braided flexi hoses.

 

[grahamrex]

I think that equates to 8lpm? And yes, mains cold. Hot water is the same tho.

 

[dilalio]

I think that equates to 8lpm? And yes, mains cold. Hot water is the same tho.

Oops! Yes of course... I halved instead of doubled it! Doh! Still very poor though!

 

[grahamrex]

Yeah, it is notoriously poor around here. That being said, I only get piping hot water at a trickle, so even more reason for concern. Sounds like there isn't an easy fix or much to try from a diy point of view?

 

[oldbuffer]

1. The design figure for the boiler is 12 lpm at a rise of 35 degrees from cold to hot.
2. If you are only getting 8 lpm I would suspect the secondary heat exchanger is partly blocked on either the DHW or boiler side or both.
3. The exchanger can be cleaned, although most engineers would replace it. Its a time v cost equation.

 

[dilalio]

Yeah, it is notoriously poor around here. That being said, I only get piping hot water at a trickle, so even more reason for concern. Sounds like there isn't an easy fix or much to try from a diy point of view?

As @CBW said... I'd go for Ideal FPR.
Their engineers are permitted to throw parts at it until it works (or doesn't).

Don't call a plumber, or even a service jockey! You need a breakdown engineer, preferably one who works on ideals a lot.

Even then, an independent, like me, has to diagnose and identify which part(s) need replacing (if any) and get it right first time as we can't return fitted parts.

As for DIY! Well, you can try and fix it until it's broken!

Remote diagnosis is impossible as there are too many variables. Sometimes, even when in front of the fault, it's hard to determine.

It's been said on here 1000 times... A lot of diagnosis work requires gas competency.
We can't share that knowledge on here and tbh, I wouldn't if I could... It's knowledge we pay for and is not gleaned along the way of a hobby or interest.

 

[dilalio]

If you are only getting 8 lpm I would suspect the secondary heat exchanger is partly blocked

He only has 8lpm incoming.