Intergas hot water issue.

[snes]

I've just helped my son remove a heap of galvanised pipe from his water system. We didn't even know it was there until it started leaking - which would explain why the water occasionally ran a funny colour - rust presumably.

However, once all pipes had been renewed, I tested all outlets, and found a good strong flow on the cold side, but a very poor hot water flow.

The boiler is an Intergas combi 36/30, so should have a good flow rate. My measures revealed a very poor 2litres per minute! The hot taps come on with a burst of pressure, then settle down to a weak flow.

The cold flow at the boiler inlet seems strong, but emerges from the hot outlet far less so.

Also, the boiler will not give hot water on demand if it is on Eco setting. Only when it is on the heat store setting.

My son is going to phone Intergas on Monday to see if they can recommend someone for its second service and also to deal with this issue. But Intergas don't seem to run a service team, they only have recommended installers - and as Tony often says, repairing is a different art to installing. Should my son still take their recommended GSR?

My only thought re this poor flow would be sediment from the galvanised pipe blocking an inlet filter on the boiler - but I don't think there is one. And the heat ex. has big water pipes within it, surely too hard to block substantially?

I know there is a wealth of Intergas knowledge on here and would welcome advice on any of the above.

Many thanks

 

[MJGas]

Big pipes in the intergas, On the hot water side ? You sure? . Do you live in a hard water area? Has the fault suddenly developed since changing the pipes or has it got worse over time?

 

[Dan Robinson]

There will be a big lump of rust choking something somewhere.

2 litres per minute probably wouldn't activate the flow switch either.

 

[Dan Robinson]

10 / 12mm tube makes up the heat exchanger.

 

[snes]

MJgas - it is a hard water area (Reading) and suspect it has got worse over time - don't know directly as it's my son's house.

Dan, the lump of rust idea seems to tie in with the rusting galvanised pipe. Are there any operations I could do to loosen/remove it without going near the c/chamber, or will a GSR have to remove the Hex to clear it?

Final thought, Dan - would the Intergas recommended installers (thats all they offer) also tend to have repair knowledge of these boilers?

Thanks as ever for all help you have given - really appreciated1

 

[Razor900]

Intergas do still use service agents occasionally but they now have an in house direct labour team.

Assuming the boiler is under warranty give them a call. Dan is almost certainly right in his diagnosis the only suprise is that you haven't got an 11 fault.

If you have any other old pipes on the water side it's worth fitting a y strainer before the boiler inlet because they won't keep coming out to the same problem free of charge if it's nothing to do with the boiler

 

[Dan Robinson]

You could try back flushing the domestic side of the heat exchanger.

Any decent boiler man will be able to strip key components out of the boiler in minutes and check for localised blockages.

Reading has pretty good pressure and flow (from my experience) . If the installer was gohe, he would have considered the use of a flow restricting service valve on the cold inlet. These are easily blocked (and cleaned).

Limescale issues would have caused big problems with shower temperatures long before the flow rate would have dropped a noticeable level.

Unless the plumbing in the house is a total basket case.

 

[Dan Robinson]

Check the heating set temperature in the boiler too. Try and set it to 60 rather than the factory setting, which assumes you have a weather sensor fitted.

 

[Razor900]

To be fair it sounds like an eco with a clogged inlet

 

[Dan Robinson]

I still prefer a paddle switch.

If I ever get mine, I will probably change the turbine for a paddle

 

[Agile]

I have done some repairs in the Reading area and the water is seriously hard.

If the CH temp has been much higher than 60 C then I would certainly expect that the boiler DHW tube is scaled.

That is part of the main HE block and would usually be treated in situ.

But very few engineers seem to know how to do that or perhaps because its a bit messy they don't want to.

It would be normal in that area to fit a scale reducer in the cold water supply to the boiler.

Tony

 

[Dan Robinson]

But very few engineers seem to know how to do that or perhaps because its a bit messy they don't want to

Good job I published a pictorial guide on how to do so in the CCR

 

[snes]

Just an update - I was desperately hoping Dan's suggestion of a rust blockage was correct, but no amount of reverse flushing helped, so I had to accept the inevitable and put it down to limescale.

And this on a boiler only 2 years old!

I hired myself a Kamco power flusher, filled it with Scalebreaker, connected up the flow and return and left it for about 90mins. The end result - full water flow again!

My only remaining task is to fit a Combimate to protect my efforts.

Must say, the Kamco was a lovely piece of kit - a joy to use!

 

[simond]

This was the same issue with the Worcesters and Ferrolis with the Bithermic Heat Exchanger, they used to scale up. Very difficult to control the temp in the hex tubes when you have no control over the water flow, so localised overheating occurs and then scale.

 

[Dan Robinson]

Nice to see the manufacturer's instructions being followed on installation