Hi, I have an older central heating system with gravity hot water ideal Mexico floor standing boiler, cylinder on landing f+e in loft, I recently had cause to switch off the bathroom radiator this radiator has lock shields both sides, I turned off the right lock shield fully and the radiator went cold as expected, I chose the right lock shield as the trv's on all the other radiators are on the right so assumed ( not necessarily correctly of course) that this was the flow side, now not sure if it's relevant or not but this radiator is on all year round, even when the rest of the radiators are off by the thermostat in the hallway, the pipe on what I assumed was the return is hotter the the pipe on what I assumed was the flow, I tested my theory of the trv being the flow side by feeling the pipe on living room radiator trv side switching on the heating and it got hot first so I thought my theory stacked up, but this didn't seem to be the same on every radiator, one question is it possible that some radiators are piped flow on the right return on the left and others vice versa, I also need to work out what order the radiators are on the circuit the kitchen and Hallway drop down from the ceiling in 15mm ( concrete floors downstairs) I'm confident it's living room first in the circuit, but don't think kitchen and hallway are 2nd and 3rd, this may not be at all relevant, and I know I'm waffling big time sorry, but is there a simple way to determine for sure, which is flow and such is return if it helps at all, the right lock shield in the bathroom had to be turned a fair few times to shut it off, my understanding is if it was the return that may have only needed 1-2 turns many thanks in advance Carl
Identifying flow and return on a bypass radiator
- Thread starter keen2learn
- Start date
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Yes.
Start with the radiator cold and the valves open and turn on the heating; the flow pipe will warm up first.
But this is a bypass radiator it's on permanently, it never goes cold as per my post
Is your hot water on constant then?
It may have been plumbed in to the hot water circuit so that you can have dry towels all year 'round.
Turn the hot water off for a few hours, turn it back on and then do as suggested above.
It may have been plumbed in to the hot water circuit so that you can have dry towels all year 'round.
Turn the hot water off for a few hours, turn it back on and then do as suggested above.
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Hi copea, yes the water is on constant, how common was/is it to have a radiator plumbed in to the hot water, in summer if the trv's are not set to off, heat can be pushed into other rads on the upstairs circuit, would this just be by convection through the pipe work thanks for your reply
so I turned the boiler off completely, and let the radiators and pipes cool completely for a couple of hours, I've just turned it back on, and felt both pipes to the bathroom radiator, it appears this radiator has the flow on the left and return on the right, unlike the living room radiator where the flow is on the right, I've also noticed the Randall 103 electro/mechanical timer the timer wheel does not turn over time but it does tick continuously, I think this may be why we have had it set to constant for several years, I vaguely remember the heating stopped working and turning the timer to constant was the remedy with little thought as to why, I guess one step will be to replace the time like with like, we have no zone valves and a stat in the hallway, one question if the return is on the right on the bathroom radiator, is there a reason it was all the way open, would this be anything to do with it being a bypass and could it be possible both lock shields are wide open, I've not yet checked how many turns it would take to shut the flow side completely, although my assumption is it would be all the way open as it is the flow, both sides have the lock shield caps and not a wheel on one side and lock shield cap on the other as I have seen online, I need to change the rad in the bathroom as the bleed key is rounded off, and it is full of air, I've just checked flow and return pipes and they are both equally scorching hot, I am slightly worried I have unbalanced the radiator, by shutting off the return rather than the flow.
No, it's not unusual for it to have been piped up that way. It's useful.
In the simplest terms, balancing means ensuring the flow reaches the radiators on the furthest branches/points of the central heating circuit.
As it's the only radiator on the circuit, the only other factor to consider is the cylinder coil.
The route around the cylinder coil in your situation will always be the 'easiest' route, so don't worry too much as you're not going to have a situation where the radiator 'steals' the flow from the cylinder.
Just set the lockshield according to how much heat you want the bathroom radiator to put out.
You can do so via the flow or the return.
The valve that is the most restrictive (i.e. closed the most) will be the one that governs the flow rate.
In the simplest terms, balancing means ensuring the flow reaches the radiators on the furthest branches/points of the central heating circuit.
As it's the only radiator on the circuit, the only other factor to consider is the cylinder coil.
The route around the cylinder coil in your situation will always be the 'easiest' route, so don't worry too much as you're not going to have a situation where the radiator 'steals' the flow from the cylinder.
Just set the lockshield according to how much heat you want the bathroom radiator to put out.
You can do so via the flow or the return.
The valve that is the most restrictive (i.e. closed the most) will be the one that governs the flow rate.
Hi Copea, thanks once again for your reply, is there a way to confirm if the bathroom radiator is definitely piped to the cylinder, I'm guessing in summer when the thermostat in the hall is set low enough not to call for heat, and the other radiators don't warm up, but the bathroom does, this is the confirmation I need, my boiler does heat and water simultaneously, also as per one of my previous questions why do other radiators warm up when the heating is not on, as I would expect if the bathroom rad is piped to the cylinder it would be on a separate circuit.
I'm assuming you have gravity hot water and pumped central heating?
It could be that you are getting gravity circulation on the heating side.
If there's no anti-gravity valve on the flow, this will be why.
If there is one, it could be stuck open.
It could be that you are getting gravity circulation on the heating side.
If there's no anti-gravity valve on the flow, this will be why.
If there is one, it could be stuck open.
you are correct, it is gravity hot water and pumped CH, I assume the flow is the pipe with the pump on it, how easy is it for a anti gravity valve to be retro fitted, as I cant see one. also one further thought, if the bathroom rad is plumbed to the hot water circuit, why do all the other radiators have trv's shouldn't one have no trv to act as a bypass. I'm now convinced the bathroom rad cant be connected to the hot water looking at the cylinder, I can see flow and return to the boiler, off the return, a 15mm pipe goes up to feed the F+E, from the flow pipe a 22mm vent also goes up to the F+E, hot water comes from the top of the cylinder via a 22mm pipe into the bathroom for the taps, above the cylinder is a cold water tank this has a 22mm feed that goes in the bottom of the cylinder to supply it and a 15mm pipe feeds the cold water tank, 15mm from the cold water tank feeds the cold taps and the shower, there is a 22mm vent from the hot going into the bathroom going to the cold water tank and a 22mm overflow from the cold water tank to the external wall in the bathroom, there are no other feeds in 15mm that I would expect to see if the bathroom rad was fed from the hot water circuit please tell me I'm missing something very obvious
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It's easy to add. It's just a single check valve.
Yes, there should be a radiator without a TRV - the room with the thermostat in.
Without seeing your pipework (ooh er) it's rather difficult to comment on the setup you have.
If the radiator warms up significantly when the hot water alone is on, then it's a good bet it is plumbed in to the cylinder circuit.
The relevant pipework may be under the floor.
Yes, there should be a radiator without a TRV - the room with the thermostat in.
Without seeing your pipework (ooh er) it's rather difficult to comment on the setup you have.
If the radiator warms up significantly when the hot water alone is on, then it's a good bet it is plumbed in to the cylinder circuit.
The relevant pipework may be under the floor.
picture 1 red flow from boiler also 22mm vent to F+E
blue return to boiler
green 15mm from return up to F+E feed
picture 2 light blue 22mm feed from cold water tank above cylinder
red overflow to outside from cold tank
picture 3 red from cylinder to hot taps 22mm
blue cold taps fed from cold water tank 15mm
picture 4 hot water out of cylinder to hot taps also vent to cold water tank
thanks for your reply once again copea hope this makes things clearer, I cant see anywhere that could be teed into to feed a radiator as no pipes go into the floor from the cylinder
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I've added some pictures of it helps at all
I've added some pictures
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