Is our oil boiler heating water to the correct temperature?

[futurejack]

Hi,
We have had heating problems for years and am trying to figure it out what the problem is now after spending a grand a few weeks ago insulating the walls with polypearl.

We always have the oil boiler set to 90 degrees and still this doesn't make the radiators that hot so the house is relatively cold. The rooms get a little warm if you close the doors - it's very uncomfortable overall.

I went out last night and took a temperature reading of the pipe carrying water into the house and the pipe coming back. I was surprised to find that the water going out is between 37 and 40c only.

If the thermostat is set to 90c should the water be 90c then?

Help! Thanks.

 

[gas4you]

Are you sure that the 90 you are setting is actually centigrade, or could it be an old stat and is actually fahrenheit?

Most boilers would not allow one to set the temp this high in centigrade anyway.

 

[futurejack]

Are you sure that the 90 you are setting is actually centigrade, or could it be an old stat and is actually fahrenheit?

Most boilers would not allow one to set the temp this high in centigrade anyway.

Hi Dave,
I think it is celcius because it's the max temp it goes to.

90f would only be 30c - Not very hot!

 

[Agile]

Is the boiler on all the time or cycling on/off?

Has the boiler been properly serviced recently ( or ever? ).

Is the oil consumption ( bill ) comsurate with the size of property?

Tony

 

[futurejack]

Is the boiler on all the time or cycling on/off?

Has the boiler been properly serviced recently ( or ever? ).

Is the oil consumption ( bill ) comsurate with the size of property?

Tony

Hi Tony,
The boiler seems to be on all the time once the timer goes off - it may just be the blower that stays on though. I know that if I turn the stat down while it's on it will switch off then.

The boiler was serviced last year but I don't think the guy was any good.


I was thinking that it must be some problem with the thermostat setting being wrong and that the boiler did not think it had to heat to 90 at all.

I was going to go out and check the wiring today but something else is bothering me now.

Could it be that it takes a few loops in the system to get the water to 90c and that somewhere along the line cold water is being introduced (or heat is being lost) stopping the boiler from getting it any hotter than 37c?

 

[Agile]

Concentrate on the boiler for the moment!

Its essential to know if its firing all the time!

If you cannot tell if its firing from the front then if you can feel the flue gasses outside ( or even the outside of the flue sometimes ) it should be obvious if its burning.

I think that all normal oil boilers turn the fan off when the boiler is not firing.

If the boiler is firing all the time but not heating up enough then the burner settings may not be providing enough power. That would mean a long way out of adjustment but will need an engineer to check. It could also be a blocked oil filter but that should not be likely unless you have allowed the tank to go completely empty.

Tony

 

[AlanE]

Help! Thanks.

Crystal ball is frozen so make & model of boiler? Rough size of property and when it was serviced did they leave the old nozzle - if so what does it say around the flats?

 

[ajstoneservices]

I wonder if the baffles have burnt through/non existent, how hot are the flues gases.

 

[futurejack]

Concentrate on the boiler for the moment!

Its essential to know if its firing all the time!

If you cannot tell if its firing from the front then if you can feel the flue gasses outside ( or even the outside of the flue sometimes ) it should be obvious if its burning.

I think that all normal oil boilers turn the fan off when the boiler is not firing.

If the boiler is firing all the time but not heating up enough then the burner settings may not be providing enough power. That would mean a long way out of adjustment but will need an engineer to check. It could also be a blocked oil filter but that should not be likely unless you have allowed the tank to go completely empty.

Tony

Hi Tony,
I've just spent the last while looking at it. I took off the front cover of the boiler and cleaned it (was quite dirty). I fired it up with the cover off and the flame seems to be good.

I've been checking the temp of pipes and stuff in the hot press and can see that the pipe bringing the hot water in goes into the bottom of the tank and the water going back out to the boiler is coming from the top of the tank. Then when the tank reaches 50 degrees near the top the motor turns on and distributes water to the radiators.

At the moment there is a constant flow of between 37 coming in and 30 going back so the boiler must not be doing it's job??! I have checked the thermostat and can see that there are two copper type filaments coming out from the bottom - these immerse into the burning chamber.

 

[Agile]

Are you confirming that the boiler is burning constantly but the flow temperature is not exceeding 37°?

If thats the case the the power inout to the boiler must be seriously low.

Depending on the construction of the boiler then totally disintegrated baffles would seriously reduce the heat absorbtion and significantly increase the temperature of the flue gas.

However, if the boiler has recently been serviced I would have thought most engineers would have noticed any serious problem with the baffles.

I would therefore expect the problem to be a reduced power input for some reason.

Tony

 

[futurejack]

I still don't understand our system fully but this is my understanding so far.

We have a tank in the hot press and a radiator distributor. The pipe coming from the boiler has an off pipe which connects to the rad distributor and the main pipe continues and connects to the bottom of the tank.

The pipe going back to the boiler is coming from the top of the water tank.

At the moment I can measure 43 degrees on the off pipe connecting into the radiator distributor. The pipe going on to the tank is only about 30c once it passes this "junction".

The nearest radiator to the hot press is 57c and this is the warmest one in the house. The other two nearest (in the bedrooms) are 48 at the top and the rest of the rad is cold. I have checked and there is no air in the rad. Sometimes the whole rad will heat up but the whole temperature will be much lower than 48. All the other rads are only a low temp (not enough to warm the room)

There is also a motor in the rad distributor system which is connected to the water tank via a thermostat. Whenever the water tank gets to a certain temperature the motor turns on - I'm not sure why this is.

 

[Norcon]

First thing you need to confirm is whether or not the boiler is firing constantly!
Does it cycle on and off?
If its cycling then you could have either a pump problem, sludge problem (ie pipes blocked) or the system is plumbed incorrectly.
Its a pointless exercise trying to explain pipe layouts IMO and also your from Ireland like myself so anything is possible. lol

 

[AlanE]

Help! Thanks.

Crystal ball is frozen so make & model of boiler? Rough size of property and when it was serviced did they leave the old nozzle - if so what does it say around the flats?

Above post seems to be totally ignored was posted for a reason!!

Details of old nozzle would enable a fair calculation to be made as to output of boiler and size of property to estimate if boiler was of sufficient size. Quite basic consideration considering original post

We have had heating problems for years and am trying to figure it out what the problem is now after spending a grand a few weeks ago insulating the walls with polypearl.

Boiler details would also enable a check to see if boiler has a pre/post purge period where the fan would operate without actually burning.

 

[futurejack]

Help! Thanks.

Crystal ball is frozen so make & model of boiler? Rough size of property and when it was serviced did they leave the old nozzle - if so what does it say around the flats?

Above post seems to be totally ignored was posted for a reason!!

Details of old nozzle would enable a fair calculation to be made as to output of boiler and size of property to estimate if boiler was of sufficient size. Quite basic consideration considering original post

We have had heating problems for years and am trying to figure it out what the problem is now after spending a grand a few weeks ago insulating the walls with polypearl.

Boiler details would also enable a check to see if boiler has a pre/post purge period where the fan would operate without actually burning.

Hi sorry,
The boiler is a Firebird popular 90. I don't know if the nozzle was changed when it was serviced but I can tell you the system is in for years and has never worked right.

I'm not sure how big the house is but it's about a 10 moderate size roomed bungalow with about 8 radiators (radiators are decent size)

 

[oilman]

A 7 degree difference across the boiler indicates heat is not getting from the flame into the water in a useful way. What speed is the circulating pump set to?

Radiator temperatures indicate the system was never balanced. Close the lockshield valves , then open by no more than 1/4 turn to start with and go from there.

This exercise will take you half a day.

If the boiler is uninsulated, and the pipes to/from the boiler are uninsulated, you are onto a loser.

If the oil filter is blocked, you will have a sooty boiler.