Intermittent Boiler Issue

[Iainmcr]

Hi Looking for a bit of advice before calling out a heating engineer.

We have a quite old Potterton Boiler which is well maintained. It has just recently developed an intermittent problem where in the mornings neither the CH or HW comes on via the controller.

If I manually boost or advance the timer then the boiler fires up ans the system is fine.

Now being a sparky I automatically thought it must be a faulty controller so swapped out the Tempus 7 for a new Drayton LP522 but this is showing the same fault.

Now the odd thing is that both CH and HW come on automatically in the evening but not mornings so I'm thinking it must be a valve sticking somewhere? The boiler is in the attic so could be affected by cold.

Could it be the 3 port valve (this is a Draytom MA1) sticking? Or as the boiler isn't firing (pump and fan a re running) is it more likely to be the gas valve, and hence a callout?

Any suggestions welcome.

 

[fixitflav]

Hi Looking for a bit of advice before calling out a heating engineer.

We have a quite old Potterton Boiler which is well maintained. It has just recently developed an intermittent problem where in the mornings neither the CH or HW comes on via the controller.

If I manually boost or advance the timer then the boiler fires up ans the system is fine.

Now being a sparky I automatically thought it must be a faulty controller so swapped out the Tempus 7 for a new Drayton LP522 but this is showing the same fault.

Now the odd thing is that both CH and HW come on automatically in the evening but not mornings so I'm thinking it must be a valve sticking somewhere? The boiler is in the attic so could be affected by cold.

Could it be the 3 port valve (this is a Draytom MA1) sticking? Or as the boiler isn't firing (pump and fan a re running) is it more likely to be the gas valve, and hence a callout?

Any suggestions welcome.

When the boiler fails to fire, does the pumo run? And is the boiler "run" wire live!? If so, the problem most likely with the boiler, if not it's elsewhere. In that case I would study the wiring diagram and do some checks on what should be happening in various circs.

 

[Iainmcr]

When the boiler fails to fire, does the pumo run? And is the boiler "run" wire live!? If so, the problem most likely with the boiler, if not it's elsewhere. In that case I would study the wiring diagram and do some checks on what should be happening in various circs.

The pump is running which makes me think that it's the boiler, but just wanted to rule out anything I could deal with myself before calling anyone out, I'll have a look at the wiring over the weekend, but as with all intermittent faults if it's electrical unless its a loose connection it's going to be a sod to track down!

 

[fixitflav]

The pump is running which makes me think that it's the boiler, but just wanted to rule out anything I could deal with myself before calling anyone out, I'll have a look at the wiring over the weekend, but as with all intermittent faults if it's electrical unless its a loose connection it's going to be a sod to track down!

OK so I guess boiler wire is live. If so just possible something like a corroded fuse holder in the boiler is the culprit. I find a squirt of contact cleaner often works wonders!

 

[Iainmcr]

OK so I guess boiler wire is live. If so just possible something like a corroded fuse holder in the boiler is the culprit. I find a squirt of contact cleaner often works wonders!

Mind you if it's inside the boiler I ain't going near it! I'm a sparky not a kamikaze ;o)

 

[FiremanT]

We have a quite old Potterton Boiler which is well maintained.

model?

 

[Iainmcr]

model?

Its a Potterton Profile 50E

 

[Grumpy Gasman]

OK so I guess boiler wire is live. If so just possible something like a corroded fuse holder in the boiler is the culprit. I find a squirt of contact cleaner often works wonders!

....and how many times have you diagnosed a corroded fuse holder being the culprit?
You shouldn’t advise on boiler related issues.

 

[Harry Bloomfield]

I had lots of problems with sticking valve actuators causing failures - usually a failure every couple or so years. I designed a neat little LED panel, a row of LED's which enabled the cause of the failure to be quickly diagnosed from which LED's were lit at the time of the failure.

 

[fixitflav]

....and how many times have you diagnosed a corroded fuse holder being the culprit?
You shouldn’t advise on boiler related issues.

I've known corroded fuse holders and connections cause problems a number of times on various appliances. He can inspect the incoming electrics without touching anything gas related. If that's not the answer there's nothing lost. Do you have a suggestion? I'm not asking you what I give advice on.

And as you're at it again, on an earlier thread about gas pipe sizing, I saw your smart comment, but the thread was locked before I could respond. I had given my pressure drop figure earlier in the thread. You (and Dan R) issued some abuse but didn't say what you disagreed with. When I asked for your pressure drop estimate, needless to say you didn't answer, with the excuse "If you think that's all there is to it you're sadly mistaken". Well that isn't all there is to it and I didn't say it is, but it is an essential step, which you're clearly incapable of carrying out.
You can please yourself whether you reply to this, I won't be reading it, I've had enough trying to talk to guys who won't have a polite discussion.

 

[Deleted member 221031]

You can please yourself whether you reply to this, I won't be reading it, I've had enough trying to talk to guys who won't have a polite discussion.

Show how you work out your pipe sizing and pressure loss ? Maybe that will help

 

[fixitflav]

Show how you work out your pipe sizing and pressure loss ? Maybe that will help

I use the Moody friction factor method, computerised of course, applicable to a wide range of fluids, liquid or gas, and flow velocities, duct sizes and shapes. Before I give more details in this specific case, let's have your, or somebody else's figure, to compare with mine. One step at a time, then perhaps we can have a sensible discussion.

 

[fixitflav]

Mind you if it's inside the boiler I ain't going near it! I'm a sparky not a kamikaze ;o)

You can look at the electrics without disturbing anything gas-related. There's probably a few push-on connectors you can pull off, apply contact cleaner, and replace. I wouldn't say it has a good chance of curing it, but if it doesn't you haven't lost anything. Last time I used contact cleaner was on the switch of a Flymo which wouldn't run. A squirt or 2 and it was fine.

 

[Deleted member 221031]

Gas engineers use predetermined figures for fittings and pipe size/length

Give me an example, including all gas appliances, distance etc and I’ll give you the pipe size and loss

 

[fixitflav]

Gas engineers use predetermined measurements for fittings and pipe size/length

I'm sure they do, that's fine. All I was asking was for others' figures, however calculated, to compare with mine.