Conventional gas boiler not fully heating water

[sxturbo]

The cylinder is copper with a good thick insulated jacket. It is in the airing cupboard directly above the boiler - literally 2ft from top of boiler to base of cylinder

Does the insulation have a plastic wrap? Or is it more modern solid foam?

It might be the cylinder is scaled up.

 

[pyounger]

I noticed you live in Bedfordshire, know it well! A very hard water area. If your boiler is maybe 20 years old, I suspect the cylinder and pipework is much older. Water moves slower in gravity systems and you may have the problem I had years back with a Potterton Neataheat boiler where the heating coil in the tank was furred up preventing / restricting water flow and therefore heat.

I don’t think there’s an easy fix for that, we only found out because our cylinder developed a leak and had to be replaced - new tank, scolding water!

 

[pyounger]

I’ve got your email, you remembered me from a previous post! That’s some memory

The photo you emailed me (shows a bright red jacket) confirms there’s no valves or thermostat. My last suggestion, furred up, seems probable

 

[ianmcd]

you could have a blocked cold feed, if you bleed the upstairs rads does water come out ok ?

 

[pyounger]

you could have a blocked cold feed, if you bleed the upstairs rads does water come out ok ?

yes, the radiators would show

 

[Ronob]

All radiators seem okay when bleeding

 

[ianmcd]

here’s the rad in the bathroom which is part of the gravity feed

yes that is normal with gravity HW, sounds like you have some kind of restriction in the gravity system, either air or as said a problem with the cold feed

 

[pyounger]

Apologies to the form, I know this chap from private messaging we’ve had in the past. He’s been mailing my tonight about this problem and as I’ve now been answering him on this forum, I’ve inadvertently been answering some of the questions being asked of him - I get carried away at this time of night

 

[Ronob]

I was beginning to wonder what was going on Paul!