Secondary circulation not working

[vetinry]

Morning

We've just about got the new ecocent cylinder installed and the pipework adjusted and it all seems to be working really well with the exception of the secondary circulation.

I can understand how it works on a gravity system, but not on a pressurised system.

The house was originally plumbed with 22mm pipework to all of the hot water points, and a 15mm return from each of these. We've simply taken the bronze pump out of its original location, and moved it next to the ecocent which is in the garage. After the pump, there is a one way valve and then the 15mm pipe is teed back into the 22mm cold water fill at the bottom of the cylinder.

The pump has been running all night but when I went to check this morning, there was still no hot water passing through it.

Any thoughts as to why it might not be working?

The pump is now installed vertically, whereas previously it was horizontal.
I read last night that it might be having difficulty opening the one way valve
Is it incorrect to tee it back into the mains supply into the cylinder?

Steve

 

[BLOD]

Lots of megaflos have secondary return plumbed this way (using a swept tee).
Is the pump pumping in the right direction?
Is the check valve the right way round?

I'm not familiar with the ecocent so might help to give manufacturer a call

 

[SimonJohns]

Also check the check valve hasn't got its self stuck closed. Now the pump is closer it may have jammed it shut


Sent from my iPhone using Tapatalk

 

[kimbo]

Check to make sure pump is not airlocked.

 

[diamondgas]

Steve .......... ya doi'n well on getting your system sorted .... 🙂 Did the cylinder not have its own secondary return connection? ... Anyhoo's ... Basics is that you have a loop circuit going past all the hot water outlets to reduce waste and deadlegs, none return stops cold water being drawn rather than hot! ... You've got a knackered pump, none return valve round the wrong way or a blockage ... IMO

 

[vetinry]

Thanks everyone
I got home last night and there now appears to be hot water circulating around the house. Didn't see Ryan and so no idea if he had to change something or whether it just started working by itself.
Steve - I know that the tank has a secondary coil but other than that and temperature sensor / pressure outlets, I don't think there were any other spare inlets for the secondary circulation.
The temperature at the bottom of the cylinder (shown on the display of the ecocent) was about 42 degrees, whereas it should be 50 degrees, and I don't want the air source pump to be working all the time, just to circulate hot water. So tonights job is to wire in a time controller because the bronze pump is just running constantly at the minute.
Cheers
Steve

 

[ecowarm]

Good idea to fit a timer on secondary circulation pump steve

 

[vetinry]

How would you set up the timer. I'd like to match it to when we're going to be using the hot water.

What is the best way to set up the timer? Is it better to have the pump spin the water around every hour or so for a few minutes, or have it running constantly for a couple of hours morning and night to co-incide with when we're most likely to need it?

I'm guessing from how long it takes to get hot water in the furthest taps without the secondary circulation turned on, that approx double this time is long enough to flush the pipes with hot water?

The old timer was mechanical and was broken, but the good thing was that it had a 24 hour clock with little "fingers" which each represented about 15 mins.

I purchased a honey single channel timer which is easy to set up but only allows a maximum of 6 actions per day (3 on / 3 off).

Depending on the best method of operation, are there any electronic timers with a higher degree of control?

Many thanks

Steve

 

[ecowarm]

Just have it circulating at times when you use the H/W, any more is a waste of energy.

Make sure the pipe work is well lagged

 

[quality]

Yeh ya don`t want it running all day and night if ya not going to be using hot water al the time

 

[vetinry]

Fantastic
I shall get the honeywell wired up tonight.

Next job is to fix 6" ducting from the main bathroom to the cylinder to make the most of the latent energy in moist air.

And then I'm going to start measuring how much energy the ecocent is using and work out how much I'm saving versus oil

Cheers

Steve

 

[ecowarm]

MMMMMMM 750 watts when running, I think you will be very happy

 

[vetinry]

Thanks ecowarm
Have you installed some ecocents then?
Steve