Always bleeding bathroom radiator

Gerry1995

We have standard two story semi-detached house with 3 rads downstairs (2 double) and 4 single upstairs. I find I am constantly bleeding the bathroom radiator, the others are all ok, anyone any ideas why this should be.

Joey the lips

How old is your heating system...

Does it have a point usually in the hot press where it is filled up. It usually has a braided hose or black valve with a pressure gague.

JohnnieK

Hi Gerry

The reason for this can be a number of things. Unfortunately I dont know the type of system you have in your house i.e. open vented or sealed system. If it is an open system (you would now because there is small water tank usually located in the attic around the main tank) this problem is quite common. It is usually caused by the pump being too strong for the system which causes the system water being pushed up the expansion pipe and into the small feed and expansion tank, this is called pitching. When this happens new water replaces it from the tank causing air introduction in the process. The air in it's nature will rise to the top and this is why you keep venting.

The way around it is to adjust the pump speed back using the lever located on the pump 1 or 2 is enough because the pump was probable over sized anyway. The other way is to get a plumber like myself to seal the system doing away with the small tank in the attic.
Older systems would normally be open vented.

If your system is sealed it is possible you might have a leak. First check the pipe that comes from the safety relief valve located at the boiler, and is piped to the outside (It meant to be). If there is a drip then the valve is passing and needs to be replaced.

If your system is an old open vented system that has been sealed it's possible that the expansion vessel has been located incorectly. The vessel should be on the negative side of the system. Every thing after the pump on the system is positive pressure back to the boiler were it becomes negative. If the vessel is located after the pump it turns the system negative and belive it or not air can be sucked in through packing glands on valves (air infiltration). The vessel should be located between the boiler and pump.

Also check around for leaking rad valves and any wet patches.

Any valve that feeds the system for top-up should be closed all the time and not left open.

Remember once a heating system is full you should never have to bleed the rads again. If you do you have a problem.

Let me know how you get on.

Gerry1995

Sorry for the lack of information, it is an open vented system, new boiler 3 yrs ago, can't remember if pump is new, so thanks JohnnieK I will adjust the pump and see what happens. There are no obvious leaks that I can see.

JohnnieK

OK Gerry1995

If it works let me know. If not you might want to look into getting the system sealed.