heatslave 15/19 overheating?

[learningtoplumb]

Hi all,
I have been to help a neighbour out this morning with a problem with his boiler (I am an apprentice!). Basically he said the boiler woke him up with all the banging etc coming from pipe work. I had a look, managed to get it going again (after it had cooled) but the pressure dial rocketed up again and it tripped the boiler stat and dumped out of the blowdown. It also did this on hot water only - had hot tap running too yet water was cold. Am I right to suggest to him that his divertor valve is faulty because it doesn't seem to be circulating? Water pressure was very low when I got there too. Thanks in advance for your help.

 

[gas4you]

Don't know this particular boiler but did you check the pump is working?

Go for simplest/basic things first then work up to more serious options

 

[Gasguru]

Check pump

Blowdown is is term used on steamboilers. The safety valve should be refered to as the safety valve and nothing else

 

[learningtoplumb]

Hi dave,
Thanks for reply. Yes pump appeared to be running ok - I did unscrew the screw thinking there may be trapped air and all I got was steam!
Hope this helps you!

 

[nortimax]

Hi all,
I have been to help a neighbour out this morning with a problem with his boiler (I am an apprentice!). Basically he said the boiler woke him up with all the banging etc coming from pipe work. I had a look, managed to get it going again (after it had cooled) but the pressure dial rocketed up again and it tripped the boiler stat and dumped out of the blowdown. It also did this on hot water only - had hot tap running too yet water was cold. Am I right to suggest to him that his divertor valve is faulty because it doesn't seem to be circulating? Water pressure was very low when I got there too. Thanks in advance for your help.

Apprentice what?

Lack of circulation resulting in a boil. Very dodgy especially if the pressure relief valve sticks or the overheat fails BANG.

 

[nortimax]

Hi dave,
Thanks for reply. Yes pump appeared to be running ok - I did unscrew the screw thinking there may be trapped air and all I got was steam!
Hope this helps you!

Pump running doesnt mean the impeller is

 

[learningtoplumb]

Gasguru,
Well I assume pump is ok although other poster said impeller may be gone. 'Blowdown' is a term everyone uses at work!! I shall put them right tomorrow! Any other ideas?

 

[nortimax]

Gasguru,
Well I assume pump is ok although other poster said impeller may be gone. 'Blowdown' is a term everyone uses at work!! I shall put them right tomorrow! Any other ideas?

How many more ideas do you need? Only other thing is a blocked pipe

 

[learningtoplumb]

Hi Nortimax,
Apprentice plumber!! 1st year just trying to help out a neighbour!! Is it a high probability that pump has gone? Surely water would/could still circulate without it just at a slower rate? Just spoken to neighbour - he said it was installed about 18 months ago with no previous problems.
Thansk for your help so far!

 

[nortimax]

Hi Nortimax,
Apprentice plumber!! 1st year just trying to help out a neighbour!! Is it a high probability that pump has gone? Surely water would/could still circulate without it just at a slower rate? Just spoken to neighbour - he said it was installed about 18 months ago with no previous problems.
Thansk for your help so far!

Nice to hear of a real apprentice. No pump, no circulation resulting in an almost instant boil hence the rapid pressure rise . Head for the pump, let it cool first though or you might need plastic surgery sooner than you'd like.

 

[learningtoplumb]

Ok thanks for that. Will have a look again this afternoon - I take it the pump is a basic replace job - I mean nothing else I have to do first? Is it common for them to go this early in life?

 

[nortimax]

Ok thanks for that. Will have a look again this afternoon - I take it the pump is a basic replace job - I mean nothing else I have to do first? Is it common for them to go this early in life?

You dont have to replace it, try checking it first, When the boiler is cool top up the system, turn down the radiator temp on the boiler, start it and remove the screw on the front of the pump it should spin, if it does you will have to disconnect the 240V nasty stuff, remove the pump head if possible and check the impeller spins at the same rate as the pump motor. Put everthing back if its ok then go look for a blockage.

 

[nortimax]

Ok thanks for that. Will have a look again this afternoon - I take it the pump is a basic replace job - I mean nothing else I have to do first? Is it common for them to go this early in life?

Don't forget to isolate and drain the boiler before you open the pump. Thinking of which.... are the flow and return taps open?

 

[learningtoplumb]

Ok thanks! Will try that later! As you said a blockage have you any idea why that would appear now?

 

[learningtoplumb]

Do you mean drain the heating down then run pump dry? That was going to be a previous question as I could see myself getting wet!! Yes as far as i know flow and return are open - no one has touched the boiler apart from myself this morning!