Baxi solo WM 40/4 PF - termostat cuts off

[madeinstein]

Hi,

My boilers runs for a while and then safety button pops out (the one on the left side of the termostat). When I set termostat to LOW it works fine, only when it's set between 1-max this things happen. I've also noticed that boiler is getting very hot quite quickly and today the flame changed from blue to slightly red.

The plumber on the phone said it might be heat exchanger. The pump is set to 3 (which is max), so I can't increase the flow.

We had this problem before but someone did something with a pressure switch and then it was fine for about a day, that's why I'm not sure if it's a heat exchanger, because it wouldn't work even then I believe.

This topic is continuation from this one //www.diynot.com/forums/viewtopic.php?t=41597

 

[bab]

Souns like a Solo 2 u may have a faulty thermostat.? check the position of the stat ( on the flow out of boiler on right) Turn power off before looking. u may have a ciculation problem. what moterised valves have u got . may have a manual by-pass open alot.is the system tank fed or sealed system. (have u got a filling loop & pressure gauge

 

[ChrisR]

Did it EVER work? Should eliminate bypass.

When on 1, do the rads all heat up, or just a couple?
Even on 1 your rads should get hot.
Circulation problem if heat's not getting around , so dud pump or blockage. Symptoms are much the same.

 

[madeinstein]

Did it EVER work? Should eliminate bypass.

Yes it worked before all other problems started (in the second topic more info)

When on 1, do the rads all heat up, or just a couple?
Even on 1 your rads should get hot.

I think only 1 out of 5 is slighlty colder (but I think it was always like that)

Circulation problem if heat's not getting around , so dud pump or blockage. Symptoms are much the same.

The pump is set to 3 so It can't increase the flow. If there is a blockage does it mean changing the whole water in the system?

 

[madeinstein]

Souns like a Solo 2 u may have a faulty thermostat.? check the position of the stat ( on the flow out of boiler on right) Turn power off before looking.

Sorry what the "stat" is?

what moterised valves have u got

Danfoss HS3 3-Port Valve 22mm (http://www.screwfix.com/app/sfd/cat/pro.jsp?cId=100126&ts=34559&id=30424)
The valve was replaced about a month ago, is it possible that it's incorectly connected? Because the plumber that was doing that said something that previously is was not corrected properly so he fixed it (but it was working for almost 2 years before)

may have a manual by-pass open alot.

Not sure what this is as well

is the system tank fed or sealed system.

There is a tank on the loft, I checked yesterday there is a water in a tank.

(have u got a filling loop & pressure gauge

sorry don't know this one as well.

 

[meldrew's_mate]

Get the next fitter to check/change the plastic 90 degree bend on the top of the air pressure switch, these have a tendancy to split.

Unfortunately the water has been muddied by all these (unnecessary?) extra works, though my hunch on the overheating would be a pumping problem (lack of water, blockage, or the pump itself)