Boiler keeps cutting out.

digisatman · 14 Jan 2008 at 19:59

hey all,

I think ive got a systems boiler, Its a Vokera Mynute 20se, and the thermostat controller is : Danfoss Randall TP9 Programmable Thermostat with DHW Control. I have noticed in the last week that, when i put temp up to switch radiators on, or switch the hot water on, the rads or water get hot (mabye 20-30 mins?), then the boiler cuts off and keeps re-starting. It cuts off, about 5-10 seconds later, it starts up again, and keep repeating this process until i manually turn temp down or switch the hot water off to switch boiler off.

Anyone know what the problem could be?

thanks

Digi

Tenzen · 14 Jan 2008 at 20:05

Your boiler thermostat (note different to the normal external one). Is causing an auto cut off possibly.

It is possible that the heat exchanger in the boiler has gone, in which case you will need a new one.

We had the saem problem this time last year.

Basically your boiler is over heating and it is cutting itself off for safety ( otherwise your boiler would melt

)

Tehre is a temp sensor in the boiler which checks the temp of the water, if it goes too high, it will turn itself off.

If you get a new boiler make sure the engineers cleanse your system using slightly acidic (tomato juice equiv at the most) to clean your radiators on the inside (note this may highlight any other problems with your rads.

Oh and you deffo need to call an engineer out.

Tenzen · 14 Jan 2008 at 20:14

These forums should give you some help:

http://www.diynot.com/forums/viewtopic.php?t=78511&view=next

Sankari · 14 Jan 2008 at 20:56

digisatman said:
hey all,

I think ive got a systems boiler, Its a Vokera Mynute 20se, and the thermostat controller is : Danfoss Randall TP9 Programmable Thermostat with DHW Control. I have noticed in the last week that, when i put temp up to switch radiators on, or switch the hot water on, the rads or water get hot (mabye 20-30 mins?), then the boiler cuts off and keeps re-starting. It cuts off, about 5-10 seconds later, it starts up again, and keep repeating this process until i manually turn temp down or switch the hot water off to switch boiler off.

Anyone know what the problem could be?

thanks

Digi

Apart from the suggestions already given, try checking your water level. If it's too low, the boiler won't want to start. Turn the tap and fill it up a bit.

digisatman · 14 Jan 2008 at 22:18

Tenzen said:
Your boiler thermostat (note different to the normal external one). Is causing an auto cut off possibly.

It is possible that the heat exchanger in the boiler has gone, in which case you will need a new one.

We had the saem problem this time last year.

Basically your boiler is over heating and it is cutting itself off for safety ( otherwise your boiler would melt )

Tehre is a temp sensor in the boiler which checks the temp of the water, if it goes too high, it will turn itself off.

If you get a new boiler make sure the engineers cleanse your system using slightly acidic (tomato juice equiv at the most) to clean your radiators on the inside (note this may highlight any other problems with your rads.

Oh and you deffo need to call an engineer out.

thanks for all the help, you think a new boiler is needed, or would they be able to stick a new part in? boiler came with house when built just over 7 years ago.

digisatman · 14 Jan 2008 at 22:18

Evangelion said:
Apart from the suggestions already given, try checking your water level. If it's too low, the boiler won't want to start. Turn the tap and fill it up a bit.

the boiler starts fine, but problem is, after a short while, it keeps cutting and restarting.

Werewolf · 14 Jan 2008 at 22:19

chances are it's a part if the bioler isn't too old

Meridian · 14 Jan 2008 at 22:22

I've had my boiler fixed for a similar problem (same symptoms, caused by a failed internal thermostat) when it was fifteen years old. Don't be fobbed off by an fitter who wants to flog you a new boiler for big commission: odds are the parts are available, but may have to be hunted down. The hard bit will be getting a part number out of the fitter if he can't fix it.

M

Tenzen · 14 Jan 2008 at 23:35

It depends on the boiler and how much the parts are for it. If they didnt make the boiler parts anymore then it will cost a premium. In our case it was cheaper to get a more economical and newer boiler than getting the part replaced as they had stopped making the part.

As its only 7 years old most chances are that the part is still manufactured - our boiler must have been 20 odd years old (valiant).

Also the newer boilers are much more efficient than an older one - approx 90% efficient nowadays (condensing boilers), compared with 60% for the older ones.

If I had a boiler that was 15 years old, I would look into replacing it for sure, boilers are jsut so much better nowadays and parts much cheaper than old, hard to source ones.

Meridian · 15 Jan 2008 at 06:55

Tenzen said:
If I had a boiler that was 15 years old, I would look into replacing it for sure, boilers are jsut so much better nowadays and parts much cheaper than old, hard to source ones.

If a new boiler used no gas at all, it would take over twenty years to pay for itself, at the rate I use gas.

M

digisatman · 17 Jan 2008 at 00:01

thanks for all replies so far, I put the pressure up to just over 2 yesterday, and now its sitting at just over 1. Even while the pressure was correct, the boiler was still behaving the exact same, works fine for a short time, then it starts cutting off and re-starting constantly.

I had a look at all the radiators while they were on, and I couldnt find any visible leaks. Heres some pics of the boiler and the control unit under it, really need to get this problem sorted soon, as its driving me crazy every time I hear it cutting off then re-starting! Any ideas?

thanks,

Digi