Heating but no hot water

[brohood]

Hi,

My heating is working fine but i'm not getting any hot water. There is hot water in the pipe running from the boiler to the pump and then from the pump towards the hot water tank. Occasionally there is hot water flowing through the tank, enough for some of the water in the tank to go from ice cold to just plain cold. However the hot water is not flowing through the tank constantly, it just comes in odd bursts and never long enough to get the water hot. The bursts have been getting progesivly shorter/less frequent resulting in no hot water now.

The overflow pipe has now started to leak, it's not a steady flow just a big gush every now and then. Is this related?

Let me know if there is any other information I can provide which will help to diagnose the fault.

I have had two plumbers out who haven't been able to fix the problem, one has changed the pump and the second recommended re-installing my whole system.

Boiler: Glowworm Ultimate
Pump: Wilo Ravenheat

 

[SilentMike]

do you not have an immersion heater?

 

[acecharly]

Sounds like a control problem to me. I dont think it would be the pump as your heating would not work either if you think about it. Is it a y-plan or s-plan?

 

[Plum Bob 66]

Sounds like a control problem to me. I dont think it would be the pump as your heating would not work either if you think about it. Is it a y-plan or s-plan?

The OP might not know the difference mate.The gushing from the overflow sounds like it might be a bit more serious though. Could be a possible split coil?

 

[Helpfulplumber]

Hi, check the three way valve. It has a sprung over ride, move it a couple of times. You get a bit of heat transfer even if the valve is stuck. Google three way valve you will see what I mean.

 

[brohood]

1. No, the immersion heater was removed years ago.

2. Sorry, don't know the difference. Probably 'Y' but not at all sure. There is a thermostat attached to the hot water cylinder, is that the control or just a left over from when there was an immersion heater?

3. Could you provide more info? Not sure if it would be possible for me to diagnose this myself. Thanks

4. Is this also referred to as the diverter valve? All the pipes leading away from it are hot when I put heating + hot water on. Can't trace the hot water pipe all the way to the cylinder as I would have to pull up a lot of floorboards, but as far as I can feel it is very hot. Occasionally hot water does reach the hot water cylinder in short bursts.

 

[lame plumber]

Airlock, clearing occasionally, blocked pipework, faulty motorised valve among potential issues.

Talk to a plumber who is able to grow a beard and has grey hair as they are likely to understand your system and its problems. Sorry to say but the fresh faced creatures seen to day are best at solving combi problems rather than s and y plan ones. Not being a smart arse but ask some quetions before you get your next plumber out as not everyone is used to old systems

 

[1967skyblue]

the thermostat on the cylinder could also be knackerd -- the bit of heat that you feel could just be reverse circulation due to poor fit or faulty motorised valve not alowing full hot water flow.

 

[mfgs]

Airlock, clearing occasionally, blocked pipework, faulty motorised valve among potential issues.

Talk to a plumber who is able to grow a beard and has grey hair as they are likely to understand your system and its problems. Sorry to say but the fresh faced creatures seen to day are best at solving combi problems rather than s and y plan ones. Not being a smart arse but ask some quetions before you get your next plumber out as not everyone is used to old systems

Bit of a harsh generalisation there. Anyone decent heating guy will be able to diagnose it regardless of age. Just as many clueless old fella's about with cracking beards and rather striking grey hair as their are young guys.

 

[lame plumber]

Bit of a harsh generalisation there.

OMHO and a few years of seeing it happen, reverse applies with me and worcester combis

 

[R1CKY]

Airlock, clearing occasionally, blocked pipework, faulty motorised valve among potential issues.

Talk to a plumber who is able to grow a beard and has grey hair as they are likely to understand your system and its problems. Sorry to say but the fresh faced creatures seen to day are best at solving combi problems rather than s and y plan ones. Not being a smart arse but ask some quetions before you get your next plumber out as not everyone is used to old systems

Careful with that brush, you're getting tar all over me!

OP, check simple things first. Check that no gate valves have been closed off. Seen this plenty of times when people have been fiddling and shut off the gate valve on the cylinder return.

Secondly, check that the zone valve/three port valve is operating. Some have position indicators, others you can't really tell with disassembling them (which is not advised unless you are competent).

If the zone valve/ three port is working and there are now valves closed, you need to start considering the possibility of a blockage or an air lock somewhere in the circuit. Are there any bleed valves on the pipework near the cylinder?

The leaking overflow could be related, most likely caused by the boiler overheating when running hot water only as the there is no where for the heat to flow.

 

[brohood]

I have been regulary bleeding the radiators (a fair bit of air) to get rid of any potential air lock, don't know if that would help with air in the hot water pipes? There are some pipes I have been bleeding near the hot water cylinder too but thats the only ones I can see specifically for the hot water (Not a lot of air coming out).

I have played around with the gate valves around the pump area and as far as I can tell none are turned off.

I will make sure the next plumber called has experience with older systems but the last two I called were middle-aged anyway. Think I might just pull up all the floor boards from the pump to the hot water cylinder before I call another plumber though.

Thanks for all the suggestion and will make sure I run through them each when I call another plumber.

 

[northstar]

where are you located ? as someone local to you on here maybe able to help you

 

[Whn1]

You haven't been playing with that stat on the cylinder by any chance have you?