Do I need to re-pressurise an electric boiler which heats water for a wet central heating system?

[JukeBoxUK]

I recently moved to a house with no gas supply, only electricity, and have a Myson Maxton slimline electric central heating boiler, which is used to heat water for supply to radiators within the house:

http://imgur.com/a/oe7ON

http://imgur.com/a/qXVUq

http://imgur.com/a/tiHxH

http://theinitiativegroup.org.uk/fs...son/MYSONMAXTONELECTRICMODELNosMB6MB9MB12.pdf

I needed to bleed some radiators and, after doing so, I thought I'd check on the pressure within the system to see whether it needed to be repressurised. But....I can't find an obviously visible pressure gauge on the boiler nor a filling loop!

Am a missing something obvious? In my previous house which had a regular gas combi boiler, I would occasionally repressurise by using the filling loop whilst watching the pressure gauge rise to the required level (i.e. 1 bar when cold).

The boiler currently operates ok, heating water for the house's radiators. Specifically, what I'm asking is:

1. If there were to be a leak in the future, or after I've bled radiators, how do I check the system's pressure?
2. If the system pressure were to drop too far, how would I know and how would I re-pressurise it?
3. If there is no way to manually repressurise the system, is it possible that it somehow automatically maintains the correct pressure?

Is anyone familiar with this system and able to give some advice? I'm confused. Many thanks!

(N.B. the boiler can be used for both central heating and hot water supply. However, I only use it for central heating. For my hot water supply I have an immersion heater in the loft above).

 

[ianmcd]

you will have an external expansion vessel possibly next to your HW tank and most likely the filling loop and guage will be there

 

[picasso]

nothing in the instructions about pressuring the boiler so probably open vent (small cistern in the loft )

 

[JukeBoxUK]

Thanks for your replies. I've gone up into the loft and found an expansion vessel, but I think this serves the unvented immersion heater.

There are two valves, one with "6 bar" written on it and one with "3 bar" written on it. I'm assuming these are pressure release valves though and serve the immersion heater, not the boiler?

Other than the immersion water heater in the loft, there is no other water tank or cistern.

I cannot find any kind of pressure gauge.

Some more pics from within the loft, showing all of the above: http://imgur.com/a/uLLKm

 

[picasso]

If it is open vent the feed and expansion will be high up in the rafters (maybe covered in insulation and boxed in ?)

 

[flameport]

This one: http://i.imgur.com/umEz6WS.jpg is for the feed/expansion. It's open vented.

The white expansion vessel is for the hot water cylinder. http://i.imgur.com/33fPfZR.jpg

The 3 bar valve here: http://i.imgur.com/7n4Zb60.jpg should not have those crusty deposits, and probably needs replacing.

 

[picasso]

When did the op sneak the first pic in ? it wasn't there when he first posted the pics.

 

[JukeBoxUK]

Ok, yes I've just found the small cistern which, as you said, was hiding up in the rafters in the dark on a little shelf, all covered in insulation - thanks!! http://imgur.com/a/60u1U

So this means it's an open vented system? And the system pressure is achieved by gravity, due to the height of this cistern above the boiler?

If so, is it also the case that the water level within the cistern is maintained and topped up automatically (from the mains supply) by some kind of float valve within the cistern itself? And therefore the pressure in the system will always be maintained this way?

Thanks again!

 

[JukeBoxUK]

When did the op sneak the first pic in ? it wasn't there when he first posted the pics.

You guys are too fast - flameport commented just after I uploaded the new pics of the cistern but before I'd posted to say I'd found it!

 

[flameport]

If so, is it also the case that the water level within the cistern is maintained and topped up automatically

Yes. The only thing to check is that there is actually water in there. Otherwise it's totally automatic.

The disadvantage of such a system is that if you get a leak, it will automatically refill, so it may not be obvious until a fair amount of water has leaked and caused damage.