Serious hot water problem

[Jamesdf5]

Hi there,

I'm not a plumber but I need some advice please about a pretty bad hot water issue i have. (I will not be carrying out any repairs myself)
My heating system is having some real problems. Can you help diagnose the problem please?
We've been living in the house for 4 months and our plumber still has not been able to fix the issue.
The problem:
Sometimes when the hot water is on, an issue occurs whereby water starts to constantly rush through the bathroom radiator. This is then followed by the pipes downstairs at the boiler making horrendous banging sounds. I have to turn it off quickly in fear that they will burst. If i turn the hot water off or turn the central heating on, the problem goes away. Seems as if the water has nowhere to go!!!
At first i thought that the problem only occurred when we had plenty of hot water in the tank. However it's been happening when our hot water is only barely warm.

Our plumber has rewired the boiler, upgraded the air release (by the Immersion tank) and added a overflow/return valve also near the tank but still we have the problem.

Our plumber now wants to re-plumb some of the piping from the boiler leading upstairs. Everything else he has tried hasn't worked so i'm not confident this will!!
Any ideas please? I'm happy to supply further information

I do have a video of the problem but this forum will not let me post it for whatever reason. I've added it to my profile under HOMEPAGE.

Thanks

James

 

[Masood]

It sounds a lot like the primary coil in the cylinder may be badly clogged up, causing the boiler to kettle, and forcing circulation through the central heating when only water is on. Once you turn the heating on, there is better flow so the banging stops. Are you constantly bleeding air out of that, our other radiators?

I would suggest a thorough powerflush...

 

[Leo21]

It sounds a lot like the primary coil in the cylinder may be badly clogged up, causing the boiler to kettle, and forcing circulation through the central heating when only water is on. Once you turn the heating on, there is better flow so the banging stops. Are you constantly bleeding air out of that, our other radiators?

I would suggest a thorough powerflush...

That or the divertors clogged or the return gate valve is shut down to far, trapping sludge and that's why it's got gradually worse.

 

[erj]

State on the boiler sound dodgy as well, sounds like the wate is not getting around

 

[Leo21]

State on the boiler sound dodgy as well, sounds like the wate is not getting around

Youve lost me?

 

[Dotty]

Think erj could have beer fingers! Or iPadicus Correcticus

I was wondering then thought he meant stat.

 

[erj]

sorry can not spell, plumb bettet

 

[Jamesdf5]

It sounds a lot like the primary coil in the cylinder may be badly clogged up, causing the boiler to kettle, and forcing circulation through the central heating when only water is on. Once you turn the heating on, there is better flow so the banging stops. Are you constantly bleeding air out of that, our other radiators?

I would suggest a thorough powerflush...

Hi, Thanks for the reply. The plumber did a powerflush 3 months ago not long after i moved in. The only radiator that water rushes through is the bathroom rad which I'm led to believe is often hooked up to the hot water!! Not sure why turning the heating on stops it. Clearly some sort of valve shuts. I have to bleed the upstairs hallway rad very often. I'm guessing it is the first in the chain?

 

[Leo21]

Hi, Thanks for the reply. The plumber did a powerflush 3 months ago not long after i moved in. The only radiator that water rushes through is the bathroom rad which I'm led to believe is often hooked up to the hot water!! Not sure why turning the heating on stops it. Clearly some sort of valve shuts. I have to bleed the upstairs hallway rad very often. I'm guessing it is the first in the chain?

If you have to vent the bathroom rad frequently you have either an incorrect cold feed and vent set up or a partial blockage. When the heating is turned on the water is free to circulate, pointing to the fact that there is some form of blockage in the hot water "route" of your heating system.

 

[Masood]

Hi, Thanks for the reply. The plumber did a powerflush 3 months ago not long after i moved in.

OK, not questioning his integrity at all, but there are powerflushes, and there are powerflushes!

The only radiator that water rushes through is the bathroom rad which I'm led to believe is often hooked up to the hot water!!

Not quite - it's often used as a system bypass, so that when valves shut down, there is somewhere for the water to flow to dissipate heat.

Not sure why turning the heating on stops it.

Because turning on the heating opens the diverter valve to the central heating circuit, which appears to have less restriction, and thus does not create a pressure build-up and kettling noises at the boiler.

Clearly some sort of valve shuts.

The opposite!

I have to bleed the upstairs hallway rad very often. I'm guessing it is the first in the chain?

Not necessarily - air will collect at high points...

It's hard to be 100% sure without looking and listening, but I still think sludge is the culprit. Leo's suggestions, also related to sludge, are strong possibilities as well. Where are you based? I'm sure someone from the forum would be happy to come and give an opinion..

 

[Jamesdf5]

That or the divertors clogged or the return gate valve is shut down to far, trapping sludge and that's why it's got gradually worse.

Still the case after power flush?

 

[Masood]

Still the case after power flush?

Depends on how thorough the flush was...

 

[Jamesdf5]

OK, not questioning his integrity at all, but there are powerflushes, and there are powerflushes!

Ha fair enough. He was here about 12 hours so I'm hoping it was a good one!!!

It's hard to be 100% sure without looking and listening, but I still think sludge is the culprit. Leo's suggestions, also related to sludge, are strong possibilities as well. Where are you based? I'm sure someone from the forum would be happy to come and give an opinion..

Have you watched the video?

I live in Roydon not far from Harlow. But i'm hopeful these opinions will be useful when i show the plumber

 

[Masood]

Have you watched the video?

Yes, I have, and based my opinion on that. I'm not far from you at all. If you want a second opinion, PM me...

 

[tamz]

Just watched your video.
1st of all get a decent plumber who knows what they are doing. This one obviously doesn't.
Your boiler is over heating and boiling to steam.
That is what is making the noise. Turning the heating on forces the boiling water around the radiator circuit cooling it.

Things to get checked.
Number 1
Boiler thermostat is reading true. In the meantime turn it down to below halfway (the dial on the top left)
Your boiler is an old myson cast iron jobbie and it looks like your hot water is fed on gravity circulation. This is very slow moving circulation (without pumps). The thermostat on it should shut down the flame at around 82ºC (180ºF) so if the thermostat is out or not reading quick enough the boiler starts boiling the water before it can shut down the flames which makes the pipes jump off the wall.
When it does this the steam needs to be released through a vent pipe which in your case should be from a pipe off the top of the cylinder coil leading directly to over a small tank in the loft (or other high level). Putting it in simple laymans terms, this pipe acts as a pressure relief
So check number 2.
As you have said you recently have had a powerflush done this leads me to suspect the vent pipe may still be capped off (this is done as a temp measure when powerflushing).

The water rushing through the rad is just one of these things. The build up of pressure needs to go somewhere so that may just be the easiest route to the feed (another open pipe you don't need to know).
Any half rsed decent plumber shuld be able to fix this in one visit but unfortunately due to a combination of factors from the top down over the years which i'll not go into, half rsed plumbers who actually know what they are doing are thin on the ground these days.

 

[DirksPlumbing]

half rsed plumbers who actually know what they are doing are thin on the ground these days.

I would love to proof you wrong. We had all those incentives where people had been enabled to leave 2 weeks courses as highly skilled and motivated tradesmen as opposed to their lame counterparts that had forgotten in year four already what they had learned in year 1 & 2. :wazzzup:

 

[Jamesdf5]

Hey Tamz,

Most definitely the most accurate reply so far. Thanks.

Just watched your video.
1st of all get a decent plumber who knows what they are doing. This one obviously doesn't.

He's fairly new in the game so I'd say lacking in experience

Your boiler is over heating and boiling to steam.
That is what is making the noise. Turning the heating on forces the boiling water around the radiator circuit cooling it.

Oh I see. Makes sense.

Things to get checked.
Number 1
Boiler thermostat is reading true.

Is that the one around the tank upstairs or one on the boiler? If so, How do I check that?

In the meantime turn it down to below halfway (the dial on the top left)

Turned it down to half way. So far it seems to have done the trick. The system is temperamental so i will wait a few more days before i do a happy dance around my living room!! lol

If this has sorted the problem fully. What do i need to do to correct it at the higher temperature?

Your boiler is an old myson cast iron jobbie and it looks like your hot water is fed on gravity circulation. This is very slow moving circulation (without pumps). The thermostat on it should shut down the flame at around 82ºC (180ºF) so if the thermostat is out or not reading quick enough the boiler starts boiling the water before it can shut down the flames which makes the pipes jump off the wall.

Oh right. That really does make sense.

When it does this the steam needs to be released through a vent pipe which in your case should be from a pipe off the top of the cylinder coil leading directly to over a small tank in the loft (or other high level). Putting it in simple laymans terms, this pipe acts as a pressure relief

There is a vent pipe by the water tank upsatirs. The plumber replaced the old one and I know it's working as air is often being released from the system.

So check number 2.
As you have said you recently have had a powerflush done this leads me to suspect the vent pipe may still be capped off (this is done as a temp measure when powerflushing).

Funnily yes originally 3 months ago after he had replaced it, yes he had forgotten to loosen the valve but its been nicely open for months now and has not helped the issue at all.

The water rushing through the rad is just one of these things. The build up of pressure needs to go somewhere so that may just be the easiest route to the feed (another open pipe you don't need to know).
Any half rsed decent plumber shuld be able to fix this in one visit but unfortunately due to a combination of factors from the top down over the years which i'll not go into, half rsed plumbers who actually know what they are doing are thin on the ground these days.

Lol I can't comment on that but you certainly seem to know what you're talking about.

Thanks so far for your help. You've been fantastic.

Regards

James

 

[Jamesdf5]

Ok i've waited a few days but the old problem is still occurring. Any more ideas please?

 

[Howsie]

Just watched your video.
1st of all get a decent plumber who knows what they are doing

There's your answer.

 

[Jamesdf5]

I'd love to but what I didn't mention was I my landlord has chosen this plumber and because I wasn't certain that he knew how to solve this issue I came to you guys for advice
Tamz: Any further thoughts would be greatly received.

Cheers

 

[Howsie]

Withhold the rent then.

#ihateslacklandlords