Netaheat Profile 60e Thermostat

[HuskyDog]

Hello,

I have a Netaheat Profile 60e. It has started to trip out about once a day. I have read posts about loose joints on PCBs, but I suspect the thermostat. My instruction manual says that I can adjust the temperature between 50 and 85 deg C. They also state that the pump overrun operates when the temperature exceeds 80 deg C. I have my thermostat set to 2, but the pump overrun still runs. Also the temperature of the flow pipe feels far more than 60 deg C. Presumably a failing thermostat would cause these sort of symptoms?

It may or may not be connected, but the case gets quite hot, particularly at the bottom.

I understand that Netaheats can be dodgy to fiddle with, but I also read lots of posts about Corgis turning up and either not knowing what to change, or just changing the expensive bits and not fixing the problem. I would like to be what we like to call at work an "intelligent customer".

Thanks

 

[Agile]

Try turning the stat down to "1".

What is done at your work?

Not Sky Tv I hope as they are on my negative comments list!

Tony

 

[ChrisR]

No worries there - you are one!.
How long does pump overrun run for - should only be a couple of minutes.
And/but yes, it sounds like the boiler stat needs replacing.

 

[speedysteve]

Whoops saw now that the orignal post was from April

Neatheats need some care - if you search on Google you will come up with some heavy stuff on deaths caused by CO leaks etc. Not sure if your one runs +ve case pressure.
Always ensure the front cover is always on when you run it and that the cover seals are in good nick - none missing, fallen out.
Work with care and think about what you are doing before you do it.
Always power off and remove fuse before dismantling. Turn gas off if you are working on that area.

I recently fitted a new overheat thermostat - read the Potterton Netaheat 16-12 Mk II Thermostat thread. This was supplied set up wrongly, so it cut out at 53 deg C when set on max - I recalibrated it...

Some questions...
Before cut out occurs do you get some heat in the rads / HW?
If you do this would indicate the pump is circulating water.
Monitor the pump sound during a run - does it slow down / stop just before the boiler trips.
Set your room thermo up so that it calls for heat and keeps the pump going the whole while.

Do you have possibility to measure the water exit pipe temp from the boiler?
Pain threshold is ~60 deg C. That pipe should hit 80 deg C before the boiler cuts out for efficient heating.
A cheap infra red temp gun is a nice toy...

 

[ChrisR]

Netaheats, Profiles, Primas and other boilers can be dangerous. Nobody without knowledge and Gas Analyser should open them. CO alarm is a sensible but not adequate measure.
They don't just gas people they can explode too.

 

[Agile]

Try comparing an IR thermometer reading with a contact thermometer and you will find they are not accurate due to the low emissivity of shiny or white painted surfaces.

Tony

 

[speedysteve]

That's a good point Agile.
Don't point them at shiny surfaces. The closer you can get the better.
I have compared mine with a contact one from work. Remarkably similar readings...

 

[Agile]

They are good for detecting the lack of insulation and for sludge and balancing rads.

Because they will not measure the temperature of pipes within boilers they are pretty useless for boiler work.

I have to say I mainly only use mine to impress customers.

Tony

 

[HuskyDog]

I have now turned the stat down to 1 and it seems to have fixed the problem for now. The pipe coming out of the pump still gets very hot, and I nearly burnt myself on it yesterday. I can't think that it should get that hot when only set to 1. Sadly, I don't have any way to measure the exact temperature. Since I have a young child I would like to keep the radiator from getting painfully hot, so I think that I will try getting the stat replaced.

In answer to other questions:

The radiators are getting hot and so is the hot water. I have increased the pump speed to its maximum since a colleague suggested that might also help.

Since it was only tripping once a day, sitting around listening to the pump is not a viable strategy.

The pump overrun runs for a few minutes.

I had to take the front off of my boiler in the summer when I was trying to drain it. It was making terrible banging noises and I read that flushing out the sludge would help. The amount of black gunge which came out was truly amazing and the banging noises are now greatly reduced. I was careful when I put the cover back to make sure that the seals were OK and that it was secure. I have just had another look, and it still seems to be securely in place. I have got a CO monitor which shows everything is OK so far.

Whilst we are on this subject, can I show my ignorance. My boiler does have positive case pressure. As I understand it, the fan sucks outside air down the outer of the flue and blows it into the case. This then flows down through the case and up through the burner and heat exchanger and then out through the middle of the flue. To my simple minded view, that means than the air inside the case is fresh air from outside. Therefore, if the case seal was faulty, all that would happen would be outside air being pumped into my kitchen and less air going past the burners. I can see that this is less efficient, but why would I then be poisoned? BTW, I have no intention of experimenting with this. If the cover has a good seal then I am happy to leave it that way.

"Intelligent customer" is a civil service term meaning that the government should understand the technical aspects of things it is buying in order not to be ripped off. Whether this is ever actually achieved in practice is another matter entirely

 

[HuskyDog]

Just a followup to say that I have had the thermostat replaced and it seems to have completely cured the problem.

Thanks

 

[ollski]

Netaheats, Profiles, Primas and other boilers can be dangerous. Nobody without knowledge and Gas Analyser should open them. CO alarm is a sensible but not adequate measure.
They don't just gas people they can explode too.

Ever put a match to the grommets where the wires come through the bottom?, and the top corners? . Manufacturer's tolerance apparantly.