Hi,
I have an issue with a single radiator on our heating system not getting hot. Would appreciate some advice. Setup is as follows:
- 2 story house (submerged basement + above ground living floor). Solid concrete construction
- Single pipe system, with a large bore (40mm) steel circulating pipe
- Circulating pipe is routed *between* the two floors - i.e. in ceiling of basement, floor of living area.
- 9 radiators on living area (above) circulating pipe - which all work fine
- 1 radiator in only heated room in basement i.e. BELOW the circulating pipe loop (I think you can guess where this is going…)
- Some radiators have thermostatic valves, some normal manual (static) valve. None of radiators have lock shield vales
- No visible lock shield valve on the overall system - on return leg etc
Obviously there are issues with above (missing thermostatic and lock shield valves). However generally the system works quite well, if a bit slowly.
The main problem is with the basement radiator which is *below* the circulating loop, and never gets hot. Unless I am being very stupid, reason is obvious. In a single pipe system you rely on a thermocycle to drive the water between the rad and main circulating pipe. Hot (less dense) water in flow pipe rises up into radiator, cold (more dense) water 'falls' out into pipe. Therefore the radiator *has to be above* the circulating loop for this to work. If it's below (this case) the HW just flows on the bypass leg of the pipe and never goes to rad.
If this is correct, I'm at a loss to understand why it was ever installed like this, and if it ever worked at all. Rest of system looks quite professionally done. It might have been added later, though this is not clear. It might be there was a swept bend or constriction, which was capable of driving the flow down into radiator but I doubt it.
To make it even odder, it looks like the feed pipe to radiator (fitted to top, with thermostat) is tapped off the circulating pipe flow after the return (which I think again is complete wrong). As it's buried in concrete I can't confirm this without a lot of disruption.
So, assuming I am correct, what are solutions? Things I can think of:
- Use an electric heater for this room (what we've been doing last 5 years)
- Convert whole system to a two pipe or micro bore system (doesn't seem worth effort)
- Run a separate two pipe loop to this radiator alone (would require some balancing valve between 2 and 1 pipe parts I assume) - again lot of work.
- Install a independent small inline pump in feed to radiator, to drive HW down into it from above.
I was favoring last one as less disruption, and could just be switched off when room is not used (most of the time).
Any thoughts on this very welcome.
Cheers
Rick
I have an issue with a single radiator on our heating system not getting hot. Would appreciate some advice. Setup is as follows:
- 2 story house (submerged basement + above ground living floor). Solid concrete construction
- Single pipe system, with a large bore (40mm) steel circulating pipe
- Circulating pipe is routed *between* the two floors - i.e. in ceiling of basement, floor of living area.
- 9 radiators on living area (above) circulating pipe - which all work fine
- 1 radiator in only heated room in basement i.e. BELOW the circulating pipe loop (I think you can guess where this is going…)
- Some radiators have thermostatic valves, some normal manual (static) valve. None of radiators have lock shield vales
- No visible lock shield valve on the overall system - on return leg etc
Obviously there are issues with above (missing thermostatic and lock shield valves). However generally the system works quite well, if a bit slowly.
The main problem is with the basement radiator which is *below* the circulating loop, and never gets hot. Unless I am being very stupid, reason is obvious. In a single pipe system you rely on a thermocycle to drive the water between the rad and main circulating pipe. Hot (less dense) water in flow pipe rises up into radiator, cold (more dense) water 'falls' out into pipe. Therefore the radiator *has to be above* the circulating loop for this to work. If it's below (this case) the HW just flows on the bypass leg of the pipe and never goes to rad.
If this is correct, I'm at a loss to understand why it was ever installed like this, and if it ever worked at all. Rest of system looks quite professionally done. It might have been added later, though this is not clear. It might be there was a swept bend or constriction, which was capable of driving the flow down into radiator but I doubt it.
To make it even odder, it looks like the feed pipe to radiator (fitted to top, with thermostat) is tapped off the circulating pipe flow after the return (which I think again is complete wrong). As it's buried in concrete I can't confirm this without a lot of disruption.
So, assuming I am correct, what are solutions? Things I can think of:
- Use an electric heater for this room (what we've been doing last 5 years)
- Convert whole system to a two pipe or micro bore system (doesn't seem worth effort)
- Run a separate two pipe loop to this radiator alone (would require some balancing valve between 2 and 1 pipe parts I assume) - again lot of work.
- Install a independent small inline pump in feed to radiator, to drive HW down into it from above.
I was favoring last one as less disruption, and could just be switched off when room is not used (most of the time).
Any thoughts on this very welcome.
Cheers
Rick
