Circulation pump on 24/7

[Teflon]

Hi All

A newbie here

i have a fuel oil boiler De Dietrich Neovo EFU29. Controling both heating and water.
I have noticed that the circ pump is not connected to the boiler for control but wired directly to a mains feed. Is this normal? I would prefer for it to switch on only when needed. Is this possible from the boiler.
Please help.

 

[bobbo]

Should be connected to a C/H controller.

 

[Teflon]

That’s what I thought but it is also needed when the hot water is selected. If I connect it to the control for the heating on the boiler board then it won’t work for the hot water. I’m confused

 

[bobbo]

My controller cost £22, it is a timer for both H/W & C/H . I don't use the timer function, I just press the 2 button's on the front, 1 is C/H the other H/W, or both together. Press once for 1 hour up to 9 hours. `Obviously it needs 2 cross over valves. Just a standard C/H system.

 

[Teflon]

I would prefer that it is switched on in some way on demand. I have two motorised valves which are triggered by the boiler. Both of these have two Free wires available from the not used microswitchs, could I use these to trigger the pump somehow??? If I can then I presume it will the be activated on demand.

 

[bobbo]

I suspect from your comments you don't have a hot water tank? I have. It takes 15 min to heat the tank for hot water. If you haven't got a tank then it "should" work like a combi boiler. In which case the manual should have instructions of the wiring to give hot water on demand. I would be guessing if I hadn't seen your system or the instruction manual. My controller operates the valves and the pump which then turns the boiler on as water is demanded. If you don't have the instruction manual try looking it up on the internet. Sorry I can't help without seeing the system.

 

[Teflon]

Hi Bobbo
I do have a tank.
I don't think my explanation is great. Hopefully these pictures will help.
As I said I would like to know if I can use the micros switch wires to switch on the supply to the circ pump.

 

[Chuck]

I would prefer that it is switched on in some way on demand. I have two motorised valves which are triggered by the boiler. Both of these have two Free wires available from the not used microswitchs, could I use these to trigger the pump somehow??? If I can then I presume it will the be activated on demand.

I think you should get an electrician who likes doing CH controls or a heating engineer to sort this lot out for you.

The normal arrangement is to have the pump controlled by the boiler, the zone valves controlled by the thermostats/programmers and the demand signal sent from the zone valves to the boiler. You seem to have all the necessary components but according to your description they have not been connected together incorrectly.

If all the parts are working, it should take someone competent a couple of hours to get sorted.

 

[ShaunCorbs]

also way way too small junction box

Heating Control Wiring Centre

 

[Teflon]

Hi All,
I have managed to find a solution myself. I had a 24v DC transformer and have used this with the motorised valves microswitches to trigger a relay to switch the pump on and off. It all seems to work like a charm. Noted about the junction box i will order an new large one to incorporate the new components as well.

 

[Stigster]

Is that a bit of 10mm plastic tube connected up to the cylinder temperature and pressure relief valve?

That doesn't look too good.

 

[Chuck]

seems to work like a charm.

Unless the boiler needs pump-overrun to avoid damaging to its heat exchanger.

 

[ShaunCorbs]

Is that a bit of 10mm plastic tube connected up to the cylinder temperature and pressure relief valve?

That doesn't look too good.

Yep looks like wire to me

 

[Stigster]

Yep looks like wire to me

It does look like it's got a nut from an electrical gland or something similar on it. What's that all about? Certainly not right whatever it is.

I'm not just being a fusspot, it's a critical piece of safety equipment.

 

[ShaunCorbs]

It does look like it's got a nut from an electrical gland or something similar on it. What's that all about? Certainly not right whatever it is.

I'm not just being a fusspot, it's a critical piece of safety equipment.

Yep not right at all looks like a wiska glad set

Don't think you can get a tundish to fit that

 

[Teflon]

Hi ShaunCorbs and Stigster.

Im sorry but i don't understand what you are talking about. 10mm plastic tube??

The pump is now controlled via a relay from the valve switch, which in turn is triggered by the boiler circuit board. The trigger comes off the board where the pump symbol is marked for both the hot water and heating. I have noticed that when the burner stops the valve and now the pump stay on for a few minuets until the triangle symbol disappears from the display.

 

[Harvest Fields]

Correct me if I am wrong. But that would be your over run

 

[Teflon]

I think I understand what you mean now. Yes there is a clear tube comping from the valve on top righthand side of the tank. This goes about 1m down into a 20mm copper pipe which in turn leads be hind the tank and to the outside, far left wall in the picture. unfortunately this is hidden by the water softener.
The tube is loose in the cooper pipe and can be easily removed.
I will take a picture later to show. Please advise if this is dangerous.

 

[Stigster]

The T&P valve on the side of the unvented hot water cylinder must be piped up to regulation because it's genuinely a serious safety issue. It's totally non-compliant at best. Just for starters the pipe were talking about must not exceed 600mm in length (called the D1 discharge pipe) before it enters the tundish, must be at least the same size as the T&P valve it's conncected to (15mm) and be made of a material capable of withstanding 95 degrees C. Apart from Tectite Flexible Metal pipe (a platic tube with an aluminium layer), no plastic I know of can take 95 degrees. It's no huge job to put it right but a G3 qualified installer needs to sort that out.

There are very specific regulations relating to how the safety devices must be installed and piped and yours is not right and even a little strange with the fittings we can see and the size and material the pipe is. Approved Document G section 3 is the relevant regs.

Only someone who holds a valid card for works on unvented hot water cylinders can work on or alter these things. Well worth getting it put right by the right plumber/engineer.

I'm not being fussy, that honestly needs sorting.

 

[Teflon]

Hi Stigstar,
Thanks for your post.
I have only just moved in to this property. I will look to get an approved plumber in to fix it. Im happy to do work on the electrical and control but not this for sure.
Im a bit embarrassed now to post the photos i have just taken.
Thank you for your advice.

 

[Stigster]

Firstly, there is absolutely nothing to be embarrassed about. You run rings (pun intended!) around me with electrical things I am certain. You can't know about everything and their regulations.

The danger you have there is that the woefully undersized, too long, D1 discharge pipe, also made of the wrong material, is possibly not far off having a stopend on the T&P valve. If the cylinder boils because of other failures the cylinder could rupture and flash to steam in the most dramatic manner.

In reality that fitting would probably blow apart and prevent the cylinder going bang but I don't like "probably" when we're talking about a couple of hundred litres of potentially boiling water/steam. Even then it'll spew boiling water and steam all over the room.