glowworm swiftflow to hot

[Rayzinzerbar]

hi has anyone had this problem before or any ideas what it could be its a glowworm swiftflow 125 electronic and basicaly when heating is off hot water works fine but when heating is on and you turn the hot tap on the water is red hot about 65c (has scalded someone) then it cools of to normal i know on these boilers there no plate heat exchanger and it runs through the normal heat exchanger but the customer has only just started getting this problem ive checked burner pressure flow rate checked the themisters checked all filters these are all fine spoke to glowworm tech and they have no ideas

 

[Deleted member 105431]

I would check the dhw ntc. Alot of these have a blending/mixer valve fitted for that reason.

 

[Rayzinzerbar]

no its not got a blending valve on it i was talking to the glowworm tech guy about that

 

[gas4you]

Could it be that they've only just started getting this problem because they have now turned the heating on and forgot what it was like last time it was on?

Sounds like a slug of HW that has been sitting it the HE, don't know how you can stop this without a blending valve

 

[Rayzinzerbar]

well thats what i said and also what glowworm said but the boilers in some offices thats rented out the tenants at this time have been there for three years and before that the landlord was there for a few years both have said that it was fine before i sugested to the landlord about using a external blending valve to try to cure the problem but he said he wants to fix the problem not hide it. one thing i did notice was the pressure needle bobs up and down during hot water mode but not on heating weather theres a pin hole in the heat exchanger but i would of thought that the mains water would push into the ch curcuit if this was the case not the other way around

 

[Deleted member 105431]

well thats what i said and also what glowworm said but the boilers in some offices thats rented out the tenants at this time have been there for three years and before that the landlord was there for a few years both have said that it was fine before i sugested to the landlord about using a external blending valve to try to cure the problem but he said he wants to fix the problem not hide it. one thing i did notice was the pressure needle bobs up and down during hot water mode but not on heating weather theres a pin hole in the heat exchanger but i would of thought that the mains water would push into the ch curcuit if this was the case not the other way around

They always do it on the early production models, fitting a blending valve is the only cure. Latter production has a cold "reservoir" before hw oulet.

 

[Rayzinzerbar]

They always do it on the early production models, fitting a blending valve is the only cure. Latter production has a cold "reservoir" before hw oulet.[/quote]

but if the costmers being there for over 5 years and it only just starts to do it there must be a problem

 

[Deleted member 105431]

They always do it on the early production models, fitting a blending valve is the only cure. Latter production has a cold "reservoir" before hw oulet.

but if the costmers being there for over 5 years and it only just starts to do it there must be a problem[/quote]

I wouldn't take the customers word as gospel. Have you checked the temp with a thermometer?

 

[Rayzinzerbar]

They always do it on the early production models, fitting a blending valve is the only cure. Latter production has a cold "reservoir" before hw oulet.

but if the costmers being there for over 5 years and it only just starts to do it there must be a problem

I wouldn't take the customers word as gospel. Have you checked the temp with a thermometer?[/quote]

yeah have checked with thermometer it was about 65c the landlord is a sparky who i do quite abit of work with though so hes quite unlikly to lie and he was there for a few years so he is sure it wasnt like this then

 

[Deleted member 105431]

check/replace the dhw ntc, gas rate and bp check. Heat exchanger may be scaled up. . . .

Quite an old but good boiler, I'd still consider fitting a blending valve.

 

[Agile]

This problem will arise because the DHW coil is always at the CH temperature. Its part of the design of the boiler. Just like the Puma or Ravenheats.

I suspect that the CH temperature may have been set or drifted higher.

Other that that I cannot suggest anything

Tony