New house, old boiler, hot water problems

[helpstuck]

Hi all,

We have just moved into a new house and inherited the boiler. It's a quite old Saunier Duval, I cannot find anything about it's model or anything, and I have done enough research before posting this to know that the brand is a bit of a dog by all accounts.

I am a bit DIY shy, but I *think* it is a combi boiler, as there is no hot water tank and it looks like it. I have taken a couple of photos below (click on thumbnails for full size images). I has a winter/summer switch that you cannot see very well.




My problem is that the pressure is just over 0.1 bar and I cannot find any valves etc to pressuring. The hot water comes out as a burst (1-2 secs) of hot hot water then goes luke warm very quickly and the boiler doesn't seem to fire when I turn the hot tap on. The temperature gauge is presumably a water temp one not a room temp one. Heating the radiators happens eventually but the system seems to fire every now and then until the flat is warm!

Some help would be very much appreciated!!

Best regards,

Dan

 

[JohnD]

pictures don't work

//www.diynot.com/forums/viewtopic.php?t=99672

 

[helpstuck]

Thanks John.

I have uploaded them directly as I cannot access mainstream hosting sites like Photobucket on this connection.

http://www.umdtalk.co.uk/1.jpg
http://www.umdtalk.co.uk/2.jpg

 

[bengasman]

Look for a silver metal braided hose, normally about 20 cm long.
If you can’t find that, look for 2 valves close enough together to be connected by this hose, one with a knob or a spindle with a slot in it, and one without.

 

[helpstuck]

Look for a silver metal braided hose, normally about 20 cm long.
If you can’t find that, look for 2 valves close enough together to be connected by this hose, one with a knob or a spindle with a slot in it, and one without.

Thanks for that - I have manged to find that behind the washing machine So I just turn that until the pressure is sufficient, 1 - 1.5 bar?

 

[gas4you]

Yep, just over 1 will do.

 

[bengasman]

1-and-a-bit for cold, 2.5 when FULLY hot, with all rads full open

 

[helpstuck]

Right, well all the radiators are on now, so I guess I might wait until the morning when it's all cold to put it on 1.

None of the radiators appear to have adjustable knobs, so I am assuming that it's all centrally controlled on the boiler. Bit of a pain - I assume there is no way to just turn off one radiator, or alternatively just have one radiator on?

But thanks for all your help guys - this stuff is so much easier when you have input from people who know what they are doing!

 

[JohnD]

can you post a pic of the rad ends?

maybe someone has adjusted all the valves and put lockshield covers on then to prevent them being altered. If so, you can take the tops off and turn the spindles. Best to use a rad knob rather than pliers as you will damage the brass spindle and round it off.

It is rare to find rads without a valve at each end

 

[helpstuck]

Morning John, I'll grab a camera and take some snaps.

One other question re: pressure though. I just this morning pressurised the system from cold, all good - pressure up to just over 1, air vented from the boiler and it is now heating up. The pressure is rising along with the post above mentioning 2.5 bar when hot, although in the FAQ thread in this sub-forum, it mentions:

After this the pressure should remain fairly stable, although a slight increase on heating up of system (and drop on cooling) is normal, as is a slight change when the pump operates.

Is slight akin to a 1.5 bar change in pressure when heating up? A little confused on that one.

Cheers,

Dan

 

[gas4you]

It could be that the exp vessel charge is a little low, also can depend on the size of the system it is fitted to.

 

[helpstuck]

Great thanks.

John, you were right regarding the radiator ends. A quick trip to the DIY shop and all sorted now. Many thanks.

I am now having a little trouble with the boiler for heating hot water.

I had to turn the temperature dial right up to max in order to provide enough heat to take a shower with a consistently hot water temp. That is all fine and makes sense giving me effectively a water temp control. My only concern is that it means I have to think about radiator and therefore CH temperature when I want hot water and vice versa as they are controlled by the same temp control. Perhaps this is a function of the boilers age?

The most concerning issues though is that the boiler has to be on, and therefore the CH on, in order for the boiler to fire when hot water is requested. Most combi boilers I have used fire on requested for hot water, and the CH is operated on the timer or on/off switch. Seems a bit odd and will mean if I want hot water I have to switch the CH on. Does this have anything to do with the winter/summer switch?

Thanks,

Dan

 

[helpstuck]

Okay, so a fresh think means I now understand the winter/summer settings and feel a little stupid for not realising earlier!

Unfortunately the problems are not fading - when the boiler is not on it seems to leak very small amounts of water. We left it with a tray under while we were on holiday for two weeks and the pressure had dropped and needed refilling. I repressurized it but now it is behaving oddly when I want hot water. I had it on the summer setting, turned the tap on, nothing fired so I switched it to winter which fired the boiler and back to summer and it continued to fire but the water did not really heat up.

Am I looking at a new boiler?