dual fuel central heating correct setup

Wearb

BDI wrote: »

Typical boards post. What is wrong with the drawing? Apart from the return arrows on the boiler going backwards but I’m guessing that’s a mistake.

MOD NOTE: If you don't stop dragging this thread off topic I will infract you for this post where you were clearly trolling. So either stop posting on this thread or be very careful to stick to the topic.

BDI

I’d go with that myself. And I’m leaving this thread good luck lads.

Dtp1979

BDI wrote: »

I’d go with that myself. And I’m leaving this thread good luck lads.

Good luck with that. It won’t work, but good luck.

Dtp1979

BDI wrote: »

I’d go with that myself. And I’m leaving this thread good luck lads.

You have the oil return joined into the gravity side of the back boiler. You’ve the oil flow teed into the bb gravity circuit. And when the oil is on it’s gonna heat the back boiler.

airliebeach

So, further investigation reveals oil boiler's circulating pump extremely hot.
And help would be great.
It's a 2 month old pump...

Dtp1979

airliebeach wrote: »

So, further investigation reveals oil boiler's circulating pump extremely hot.
And help would be great.
It's a 2 month old pump...

What do you need to know? I’ve already explained that the system is piped arseways. You really need a good plumber in there. There’s no quick fix. The one bit of advice I’d give, and urge, is not to light the back boiler until it’s fixed.

airliebeach

Dtp1979 wrote: »

What do you need to know? I’ve already explained that the system is piped arseways. You really need a good plumber in there. There’s no quick fix. The one bit of advice I’d give, and urge, is not to light the back boiler until it’s fixed.

Thanks Dtp for all the info.
Will have proper look at what you said tomorrow evening and will prob come back with more questions.
For now though, the drawing is accurate, just the setup in the house seems pretty crap based on your feedback. I def won't be attacking the issues you raised, myself, but I'd like to fix the immediate problem of the oil burner switching off. Baring in mind it's been working without a hitch for last 2 months...
Have you any ideas why the pump is red hot? Generally these should be warm but not scaldy right?

jimf

airliebeach wrote: »

Thanks Dtp for all the info.
Will have proper look at what you said tomorrow evening and will prob come back with more questions.
For now though, the drawing is accurate, just the setup in the house seems pretty crap based on your feedback. I def won't be attacking the issues you raised, myself, but I'd like to fix the immediate problem of the oil burner switching off. Baring in mind it's been working without a hitch for last 2 months...
Have you any ideas why the pump is red hot? Generally these should be warm but not scaldy right?

its quite possible the pump has failed

system could be low in water

your boiler is cutting out so fast because the stat is doing its job for whatever reason there is no water circulating through the boiler

airliebeach

Dtp1979 wrote: »

Ok genius, seeing it at a 2 second glance I can see there is no gravity circuit. There’s a non return valve Beside the back boiler, making the back boiler essentially a bomb, and it’s a combined feed and expansion setup too. All wrong. Now, that’s only 2 seconds. If I get a chance I’ll take a proper look.

Yeah the feed/expansion combo looked wrong even to my ignorant eye. But unfortunately that's actually the way it is. Where should the feed be connected?

airliebeach

jimf wrote: »

is this from cold with no back boiler running

Yep.
Also if backboiler is running at same time, oil boiler will still cut out after a while

airliebeach

BDI wrote: »

The feed and expansion tank come off the flow side of the back boiler. I would say having a non return valve on the return side would not make it any less of a bomb than before. Ok I agree we could take the feed tank into the return between the non return valve and the boiler return but that’s why we are here, to share knowledge.

Why is it bomb-like?
It has unobstructed route to expansion tank...

airliebeach

jimf wrote: »

the typical ans to anybody with a combined heating system that incorporates a back boiler would be to get a professional that knows and understands how the 2 can be combined to work safely

a back boiler not installed properly without an unobstructed gravity circuit is not something you mess with

I realise a pro would be best. But this system is already in place and I'm just trying to figure it out to fix my immediate problem.
Can you explain exactly what is a gravity circuit please?

airliebeach

Dtp1979 wrote: »

-Ok op, getting back to this now. The blue line going to the attic from the pump, what’s happening there, it seems to terminate in the open attic?

- combined feed and vent in the attic is incorrect.

- there should be absolutely no non return valve on the primary circuit. Especially where it is!

-there’s no gravity circuit from the back boiler to the cylinder.

- there should be a dual coil cylinder installed but this isn’t absolutely necessary once the solid fuel is piped correctly to the cylinder. Using a single coil just means that the oil heating won’t heat the domestic hot water.

There’s also a valve on the coil return. That’s an absolute no no.

Long story short op, you need a professional to sort this out. It’s not a diy job.

Thanks for this post.
Yep just terminates in the attic. What was it intended for. Its a smaller pipe. Possibly for the feed?

Combined feed and vent always a bad idea? Or just poorly done here?

No non return valve? What do you mean exactly by primary circuit? (stupid question I know). What harm is a non return valve as long as its fitted in correct direction? Where should it be?

What is the gravity circuit? Maybe I have this. But if pipe disappears under ground then my knowledge goes with it...

I've a single coil. Both boilers connected to it.

airliebeach

jimf wrote: »

its quite possible the pump has failed

system could be low in water

your boiler is cutting out so fast because the stat is doing its job for whatever reason there is no water circulating through the boiler

Think you could be right about pump Jim. Although it is rotating. Not sure of internal makeup of pump but maybe fins broke or something. But sounds OK!!

jimf

airliebeach wrote: »

Think you could be right about pump Jim. Although it is rotating. Not sure of internal makeup of pump but maybe fins broke or something. But sounds OK!!

if this pump was only fitted 2 months ago get the installer back

John.G

BDI wrote: »

Surely you could have drew a picture by now instead of trying to have an internet fight with me, do you want me to draw my picture? Of what I’d do?

A little late but came across this some time ago, it may be of some help.