Is there a simple way to check to output of my daughters pump.They have an Ideal Classic boiler,the flow to the 3 way valve was cold untill I put the pump to number 3.The flow is now hot & so are the outlets to tank & Rads,the hot water is hot but the rads are cold.The boiler only fires for 20 / 30 secs then fails but the over temp switch does not operate.The system had a new Rad fitted yesterday and all the Rads have been bled of air.Please help we are freezing!!!!!
how to test CH Pump
- Thread starter wedgy3
- Start date
Sponsored Links
Sponsored Links
Hmn ? three way valve. Do I assume the system was drained down.
Was the 3 way valve put to mid position for draining and re filling.
Rads were bled but was the pump also bled.
To avoid air locks when fitting or replacing a rad, it's wise to run off a bucketful of water from the inlet and outlet valve after refilling, this gives a easy escape route for any air lock.
Air is easily compressed and the circulating pump can not move it easily because there is too much resistance.
Also does your system have a by pass valve? If so and it is open too far then water will take the easiest route back to the boiler instead of rads which offer more resistance.
Also have you removed the pump for examination. Sometimes the inlet and outlet holes become reduced in size with sludge. This will have a adverse effect on the flow. The hot water in the boiler can't get away fast enough so it overheats and boiler stat closes down boiler.
HW is hot but rads are cold? Now that I feel is most likely the 3 port valve.
First you need to prove the room stat works ok. Next, does the valve move to the mid position. If it does then you should get the rads hot, but probablely not for long. As soon as the HW side is satisfied the valve should move across to the CH position. It could be the motor is faulty and not getting to the CH position, or if it does get there then you may have faulty micro switch. You should be able to remove the actuator head offf the valve spindle and watch the underside as you try the various positions by altering the room and cylinder stats to 'satisfied' or 'not satisfied'.
Also test the valve spindle for stiffness.
In order to locate a problem, I'm afraid you have to know how the system works in some detail and know of methods of testing. There's plenty been written on this forum about 'Y' plan and 3 port mid position valves.
Was the 3 way valve put to mid position for draining and re filling.
Rads were bled but was the pump also bled.
To avoid air locks when fitting or replacing a rad, it's wise to run off a bucketful of water from the inlet and outlet valve after refilling, this gives a easy escape route for any air lock.
Air is easily compressed and the circulating pump can not move it easily because there is too much resistance.
Also does your system have a by pass valve? If so and it is open too far then water will take the easiest route back to the boiler instead of rads which offer more resistance.
Also have you removed the pump for examination. Sometimes the inlet and outlet holes become reduced in size with sludge. This will have a adverse effect on the flow. The hot water in the boiler can't get away fast enough so it overheats and boiler stat closes down boiler.
HW is hot but rads are cold? Now that I feel is most likely the 3 port valve.
First you need to prove the room stat works ok. Next, does the valve move to the mid position. If it does then you should get the rads hot, but probablely not for long. As soon as the HW side is satisfied the valve should move across to the CH position. It could be the motor is faulty and not getting to the CH position, or if it does get there then you may have faulty micro switch. You should be able to remove the actuator head offf the valve spindle and watch the underside as you try the various positions by altering the room and cylinder stats to 'satisfied' or 'not satisfied'.
Also test the valve spindle for stiffness.
In order to locate a problem, I'm afraid you have to know how the system works in some detail and know of methods of testing. There's plenty been written on this forum about 'Y' plan and 3 port mid position valves.
DIYnot Local
Staff member
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local
