I've been researching through various forums in a desperate attempt to work out the weird and wonderful water heating system in my house, as i have a few problems!
First problem is that even when the heating is off during the summer, when the hot water comes on, at least one of the upstairs radiators gets hot (i have to turn off at the valve).
The boiler when the central heating is on, tends to come on for about 3-4 minutes, then turns off for about 10 minutes, then comes on again - this continues, so the radiators take an age to warm up - even when the thermostat is set to max. I've replaced the valve on the central heating, replaced all the old wiring, and replaced the thermostat and tested it - still the same.
I had to remove the hallway radiator at the weekend to re-secure the wall mountings, and when i was removing, i was initially going to drain the whole system, then after about 5 minutes of draining decided to just drain the radiator (I know, very stupid!). upon refitting, i bled the whole system and cleared any air - at first the upstairs radiators got hot, but not the downstairs ones (including the one i'd removed). Then all of them stopped getting hot water, completely. I've tried bleeding the radiators to see if any air comes out with the water, bled the air valve at the cylinder coil hot feed, and at the pump, all with no success. The only way any hot water is felt through the pipework (feed or return) is when i bleed the radiators for a long time - then the water gets warm at the feed and at the oppostie top corner where i'm bleeding from! The return never warms up. The cold feed is also working ok, so the system is not low on water either. As a last resort last night i completely drained the system, and then refilled, and bled the radiators, bottom to top floor - all filled ok. The hot water feed from the boiler got hot no problems, and the water was travelling past the CH motorised valve, but not even the slightest bit of heat reaches any of the radiators, through either feed to them. The hot water is still working no problem, so the cylinder coil is working fine. I'm fresh out of ideas!
To give you a better understanding, I have an old back boiler, running a fully pumped, vented S Plan system, complete with a single heating zone. Both the CH and HW motorised valves are ok (tested), and all the wiring is ok. The thermostat is fine, and the pump seems to be circulating hot water ok (well the feed through the cylinder coil is working anyway!). The only quirk i've noticed is the hot water valve is on the return out of the cylinder coil instead of the hot input - does this matter? I suspect it's because the coil feed is tee'd off after the pump as a 15mm pipe as opposed to 22mm which is what the output from the coil is (in itself seeming a bit strange).
The radiators are a mix - one downstairs and the two upstairs use 15mm pipe, but theother 3 downstairs are only the 10mm microbore pipe, so i suspect they have just been tapped off the pipes elsewhere at a later date.
The system was serviced about 12 months ago and all was fine (well apart from the slow CH issue - but summer made me forget!)
From what i've researched, it would appear that the pipework is all connected correctly to the expansion tanks, and all the pipework seems correct -apart from the wrong positioning of the HW valve. This tends to suggest that there is a blockage in the radiator return circuit; but i can't seem to get it to move again. tried turning off all the radiators bar one for force higher pressure through, but even that doesn't work! Any suggestions??
Also, with regards to hot rads with no CH on - this would point to reverse circulation going on somewhere, correct?
Thanks in advance - i've tried to figure it out myself, but 2 days of now heat is starting to affect my thinking!!
First problem is that even when the heating is off during the summer, when the hot water comes on, at least one of the upstairs radiators gets hot (i have to turn off at the valve).
The boiler when the central heating is on, tends to come on for about 3-4 minutes, then turns off for about 10 minutes, then comes on again - this continues, so the radiators take an age to warm up - even when the thermostat is set to max. I've replaced the valve on the central heating, replaced all the old wiring, and replaced the thermostat and tested it - still the same.
I had to remove the hallway radiator at the weekend to re-secure the wall mountings, and when i was removing, i was initially going to drain the whole system, then after about 5 minutes of draining decided to just drain the radiator (I know, very stupid!). upon refitting, i bled the whole system and cleared any air - at first the upstairs radiators got hot, but not the downstairs ones (including the one i'd removed). Then all of them stopped getting hot water, completely. I've tried bleeding the radiators to see if any air comes out with the water, bled the air valve at the cylinder coil hot feed, and at the pump, all with no success. The only way any hot water is felt through the pipework (feed or return) is when i bleed the radiators for a long time - then the water gets warm at the feed and at the oppostie top corner where i'm bleeding from! The return never warms up. The cold feed is also working ok, so the system is not low on water either. As a last resort last night i completely drained the system, and then refilled, and bled the radiators, bottom to top floor - all filled ok. The hot water feed from the boiler got hot no problems, and the water was travelling past the CH motorised valve, but not even the slightest bit of heat reaches any of the radiators, through either feed to them. The hot water is still working no problem, so the cylinder coil is working fine. I'm fresh out of ideas!
To give you a better understanding, I have an old back boiler, running a fully pumped, vented S Plan system, complete with a single heating zone. Both the CH and HW motorised valves are ok (tested), and all the wiring is ok. The thermostat is fine, and the pump seems to be circulating hot water ok (well the feed through the cylinder coil is working anyway!). The only quirk i've noticed is the hot water valve is on the return out of the cylinder coil instead of the hot input - does this matter? I suspect it's because the coil feed is tee'd off after the pump as a 15mm pipe as opposed to 22mm which is what the output from the coil is (in itself seeming a bit strange).
The radiators are a mix - one downstairs and the two upstairs use 15mm pipe, but theother 3 downstairs are only the 10mm microbore pipe, so i suspect they have just been tapped off the pipes elsewhere at a later date.
The system was serviced about 12 months ago and all was fine (well apart from the slow CH issue - but summer made me forget!)
From what i've researched, it would appear that the pipework is all connected correctly to the expansion tanks, and all the pipework seems correct -apart from the wrong positioning of the HW valve. This tends to suggest that there is a blockage in the radiator return circuit; but i can't seem to get it to move again. tried turning off all the radiators bar one for force higher pressure through, but even that doesn't work! Any suggestions??
Also, with regards to hot rads with no CH on - this would point to reverse circulation going on somewhere, correct?
Thanks in advance - i've tried to figure it out myself, but 2 days of now heat is starting to affect my thinking!!
