Think my flow & return are the wrong way round

[oldskoo1]

My boiler seems to be short cycling and could possibly be due to air lock. I can hear trickling inside.

The house is a 5 bed, 3 storey with an Ideal Classic FF380 on the ground floor with the megaflo and pump on the middle floor. With 20 rads i suppose it was assumed the pump needs to be on it's highest setting, 3. I think this is causing air as the further rad needs bleeding every few weeks.

I raised the pressure at touch to 1.6bar and at warm it's 1.7bar.

I can't seem to shift the air (bled pump / rads), althought it's only the first day i'm running it on pump speed 2, maybe it needs time to settle? (there is an autovent by the pump).

But in my quest to solve this air problem and short cycling i read the manual and discovered the flow and return pipes are connected to the wrong ports on the boiler.

According to the manual, flow is right, return is left (front view). Mine are the opposite, the left pipe gets hot first. It seems the boiler monitors the temperature of the return pipe, as this is the flow (on mine), it's going to be premature shut off right? This could be the cause of the short cycling if i have this right and there is not some funny stuff going on that i'm not aware of / have misunderstood.

Would this also cause the air problem or is this most likely down to the pump speed 3 causing water to hit the impeller at high speed creating air?

The only red herring is, the boiler short cycles from cold and it's first turn off is around 5 mins. At this point the water is certainly not the 77c degrees the boiler stat is set too (setting 5 of 6). So i assume air lock is compounding the issue. To note: pump is installed with arrow pointing away from the boiler.

Any advice appreciated

 

[rjm2k]

I'm no expert but I'd guess your pump is on the wrong way round.

 

[oldskoo1]

I added a bit to the end of my post perhaps just after you read it? The pump arrow is pointing away from the boiler, is this correct?

 

[CBF]

the pump might have the arrow pointing away from the boiler (which is correct as it should be on the flow) but which pipe is it on ?

plus this is an old boiler have you had any alterations that would account for you thinking after all this time that it's piped wrong ?

 

[Agile]

That means nothing if you dont say where your pump is fitted!

The pump should be directed so that the flow comes out of the boiler on the right in your case.

Assuming your boiler has the pipe connections at the top it would be unusual to have air inside the boiler during normal operation with the correct flow direction.

The return connection has an internal tube which discharges the return water at the bottom of the boiler!

Tony Glazier

 

[oldskoo1]

The pump is fitted on the middle floor, next to the hot water tank in the airing cupboard.

Pipes coming through the floor so not sure how to tell.

All's i can say is, pipes coming out the top of the boiler, left is hot first, pipe going into pump upstairs is also hot first, arrow pointing away from boiler (upwards).

Just to clarify my flow is the left pipe (coming out top of boiler) - this is the hottest first, according to manual it should be the right hand side pipe which is the flow.

I've only moved into this house in September, only really been last few weeks i've noticed this short cycling etc now the CH is active. That aside air is still a problem, furthest rad needs regular bleeding and trickling water noises in boiler. I'm hoping pump speed of 2 will solve providing all rads get heat. If not might need a modulating pump maybe, not sure.

Thanks

 

[oldskoo1]

Here are some pics of the system

 

[Agile]

Just turn the pump round.

To make it look nice you can take off the motor head and rotate that so the writing is the right way up and the connections stay on the left.

Apart from a rather old boiler its quite a nice neat installation!

Tony

 

[oldskoo1]

Thank you

What about the boiler sensor on the return pipe that is currently my flow pipe - could it be causing the short cycling? By thinking the return is too hot?

Would changing the pump around cure the air too?

 

[JohnD]

pipes coming out the top of the boiler, left is hot first,

so currently the left side is being the Flow pipe.

 

[oldskoo1]

pipes coming out the top of the boiler, left is hot first,

so currently the left side is being the Flow pipe.

Yes thats right - it's the first one to get hot, return pipe being right on mine warms up after a few mins.

I think it's the wrong way round for my boiler, hence the short cycling maybe?

 

[Agile]

The air in the boiler and the short cycling should both be cured by correcting the flow direction!

Tony

 

[fine tune]

the pump , motorized valves, auto air vent, and pipework in airing cupboard are all in correct position the problem is the pipes between boiler and airing cupboard are crossed over and need changing over under floor boards or where ever you can gain access. turning the pump round will make the pipes run backwards in airing cupboard as apposed to how the boiler is now . which could cause a differant set of problems. cheers.

 

[oldskoo1]

Perhaps the gas engineer could adjust the pipe work going out the top of the boiler

There seems to be some room between the top and ceiling

 

[Boilerman2]

That's what I would do Oldschool!
turning round the pump would correct the flow direction through the boiler, but it would be wrong everywhere else, one side effect of turning the pump would be a loud bangin noise every time one of your 2 port motorised valves closed - because they also are flow direction sensitive!