Hi Folks,
Firstly, as will become blindingly obvious fairly soon, I know nothing of central heating systems (hence being here for help). I bought my first ever house a little over a year ago, and was content until recently just to know that the boiler had "Potterton" printed on it and very little else.
A a couple of months ago one of the main downstairs radiators cooled down. After noticing, I was given a crash course in bleeding radiators by a friend (see, I told you I know nothing of central heating systems). This helped for a couple of days, but soon it was cold again and no amount of bleeding helped. I couldn't really afford to have it professionally looked at (and yes, I know I can't afford not to either), so decided that as long as the rest of the radiators carried on working - I could live without it.
Now I'm having problems with a second radiator downstairs, and it has occured to me how little I know about my own central heating system. Whilst any suggestions as to the radiator problem would be great - my main reason for this posting is to familiarise myself with my system before attempting to drain/refill it.
I've done a little reading on this site (as well as others) - but a lot of the answers, and some of the questions for that matter, assume a basic level of knowledge which I obviously lack.
A little background to my system... There is a Potterton 40eL gas boiler in the kitchen with a Randell-102 "A-On, B-Off, C-On, D-Off" style mechanical clock next to it (with a "Water Only, Off and Water/Heating" rocker switch on the side). A number of radiators upstairs and down of varying sizes. A thermostat in the living room. The hot water tank is upstairs is a small cupboard with another thermostat, a temperature sensor attached to the tank, a Grundfos pump and a three-way valve (Potterton PMV3). The house was built 12 years ago, but I've no idea if the central heating is the same age as the house. I live in a "soft" water area.
How can I check if my bleeding the radiators has removed too much water?
As I understand it, the water in the radiators is exactly the same water as when I moved in. I'd read somewhere about a pressure gauge. But I have been unable to find one anywhere. I'm just concerned with all the bleeding maybe there isn't enough water for everything to work properly.
Is the expansion vessel the small tank in the loft?
Having searched around a bit, I find two insulated water tanks in the loft - both appear to be linked to the hot water tank. One is considerable larger that the other (maybe four/five times bigger by volume). Would I be right in assuming the larger one is a "feeder tank"? Would I also be right to assume that this is the water that eventually come out of my hot taps? I've read somewhere about an expansion vessel - is it likely that's what the smaller tank is? (I'm assuming that since water expands when heated, that the water in the radiators need somewhere to expand into).
Any special precautions to take before draining the radiators?
I had intended to switch the system off at the switch on the side of the A-B-C-D clock, then attach a hosepipe to one of the drainage pipes at the bottom of one of the downstairs radiators and open the valve. Anything else I need to worry about? I'd heard about various "flushing" chemicals, but would they be essential or optional extras? All the downstairs radiators have drainage points, do I need to do them all? And if so, all at once or one at a time?
Draining from where?
Is there valve or something I need open at the "top" of the system? My understanding of sealed systems is that water will only pour out the bottom if air can rush in at the top (else a vacuum will form). Is there something I need to turn/open or will the air come in through the small tank I've assumed is the expansion vessel?
Will the small tank automatically refill the radiators?
The small tank has a ballcock in it (although I hadn't noticed a cold water feed). Is this likely to be to refill any water lost/drained from the radiators or is it just likely to be an overflow when the system is refilled via other means?
Refill where?
Assuming the ballcock in the little tank is for overflow prevention... Would I refill the system from the bottom or the top? I could forsee problems with air blockages by just pouring water in the top (maybe into the little tank?) - but that would leave only filling from the bottom up. In which case, how? Where? And would I need someone in the loft near the little tank to tell me when it's "full"?
Refill with just water?
Assuming I can empty and refill the radiator system, is that it? Or is there some additive or something that needs to go in too? There seems to be some kind of logic to adding something to the water to reduce the buildup of "whatever" - but where that idea came from, I've no idea. If something like that is necessary - is it just a case of pouring that something into the small tank? Would it need to be measured?
Sorry for such a long post.
I have some specific questions about the three-way actuator, the timer clock and a few other bits and pieces - but I'll wait to see what sort of response I get to this first.
Thank in advance,
-Baz
Firstly, as will become blindingly obvious fairly soon, I know nothing of central heating systems (hence being here for help). I bought my first ever house a little over a year ago, and was content until recently just to know that the boiler had "Potterton" printed on it and very little else.
A a couple of months ago one of the main downstairs radiators cooled down. After noticing, I was given a crash course in bleeding radiators by a friend (see, I told you I know nothing of central heating systems). This helped for a couple of days, but soon it was cold again and no amount of bleeding helped. I couldn't really afford to have it professionally looked at (and yes, I know I can't afford not to either), so decided that as long as the rest of the radiators carried on working - I could live without it.
Now I'm having problems with a second radiator downstairs, and it has occured to me how little I know about my own central heating system. Whilst any suggestions as to the radiator problem would be great - my main reason for this posting is to familiarise myself with my system before attempting to drain/refill it.
I've done a little reading on this site (as well as others) - but a lot of the answers, and some of the questions for that matter, assume a basic level of knowledge which I obviously lack.
A little background to my system... There is a Potterton 40eL gas boiler in the kitchen with a Randell-102 "A-On, B-Off, C-On, D-Off" style mechanical clock next to it (with a "Water Only, Off and Water/Heating" rocker switch on the side). A number of radiators upstairs and down of varying sizes. A thermostat in the living room. The hot water tank is upstairs is a small cupboard with another thermostat, a temperature sensor attached to the tank, a Grundfos pump and a three-way valve (Potterton PMV3). The house was built 12 years ago, but I've no idea if the central heating is the same age as the house. I live in a "soft" water area.
How can I check if my bleeding the radiators has removed too much water?
As I understand it, the water in the radiators is exactly the same water as when I moved in. I'd read somewhere about a pressure gauge. But I have been unable to find one anywhere. I'm just concerned with all the bleeding maybe there isn't enough water for everything to work properly.
Is the expansion vessel the small tank in the loft?
Having searched around a bit, I find two insulated water tanks in the loft - both appear to be linked to the hot water tank. One is considerable larger that the other (maybe four/five times bigger by volume). Would I be right in assuming the larger one is a "feeder tank"? Would I also be right to assume that this is the water that eventually come out of my hot taps? I've read somewhere about an expansion vessel - is it likely that's what the smaller tank is? (I'm assuming that since water expands when heated, that the water in the radiators need somewhere to expand into).
Any special precautions to take before draining the radiators?
I had intended to switch the system off at the switch on the side of the A-B-C-D clock, then attach a hosepipe to one of the drainage pipes at the bottom of one of the downstairs radiators and open the valve. Anything else I need to worry about? I'd heard about various "flushing" chemicals, but would they be essential or optional extras? All the downstairs radiators have drainage points, do I need to do them all? And if so, all at once or one at a time?
Draining from where?
Is there valve or something I need open at the "top" of the system? My understanding of sealed systems is that water will only pour out the bottom if air can rush in at the top (else a vacuum will form). Is there something I need to turn/open or will the air come in through the small tank I've assumed is the expansion vessel?
Will the small tank automatically refill the radiators?
The small tank has a ballcock in it (although I hadn't noticed a cold water feed). Is this likely to be to refill any water lost/drained from the radiators or is it just likely to be an overflow when the system is refilled via other means?
Refill where?
Assuming the ballcock in the little tank is for overflow prevention... Would I refill the system from the bottom or the top? I could forsee problems with air blockages by just pouring water in the top (maybe into the little tank?) - but that would leave only filling from the bottom up. In which case, how? Where? And would I need someone in the loft near the little tank to tell me when it's "full"?
Refill with just water?
Assuming I can empty and refill the radiator system, is that it? Or is there some additive or something that needs to go in too? There seems to be some kind of logic to adding something to the water to reduce the buildup of "whatever" - but where that idea came from, I've no idea. If something like that is necessary - is it just a case of pouring that something into the small tank? Would it need to be measured?
Sorry for such a long post.
I have some specific questions about the three-way actuator, the timer clock and a few other bits and pieces - but I'll wait to see what sort of response I get to this first.
Thank in advance,
-Baz
