New install on an old system.

[Dannypipe]

Two ideal logic plus 30kw on a cascade with LLH open vent is simple and works a treat. Only problem u got is the listed status. Do they have consent for flues and plant!!? Magnanaclean 28mm on return from LLH. Boilers need to be co current connections when in cascade. Boiler 1 gets flow first and ret seconds and boiler two gets flow second and return first.

Thanks for that.

Can you explain why you have to configure the f&r's like that? To maintain an equal flow rate I'm expecting.

I'm also going to quote to fit a sequencer though looking at the other quotes, they haven't. I've installed one before and it's worked well. I used the Warm World model. In fairness it broke after two years (a relay went) but the new one has been in a couple of years now and is all good.

 

[Dannypipe]

Here's the current install. Nice aint it!?

 

[Ermintrude]

Thanks for that.

Can you explain why you have to configure the f&r's like that? To maintain an equal flow rate I'm expecting.

I'm also going to quote to fit a sequencer though looking at the other quotes, they haven't. I've installed one before and it's worked well. I used the Warm World model. In fairness it broke after two years (a relay went) but the new one has been in a couple of years now and is all good.

It's what ideal tell you to do when cascading them, assume its to maintain even flow. U need only connect the pump for the boilers to the boilers and the system pumps to controllers

 

[Kev the gas]

Danny I may be able to help you there !!

I am removing a SoSolar system this week
http://www.ukplumbersforums.co.uk/renewable-energy/60513-rusting-solar-expansion-vessel.html

I was going to butcher the system whilst removing for ease, but if you want it I will take care.

The pump station will need a thorough flush, the Pressure gauge I presume needs a little clean of the hole.

There will be a cylinder sensor and control panel.

Please let me know asap as it is coming out on Thursday, the customer has had enough of a poorly designed/installed system.

Kev

 

[Dannypipe]

Mate that would be much appreciated and of course I'd be happy to pay you. Let me know what you want for it mate. PM me if you want. The mother in law will be pleased as it can stay in her garage until the spring!! LOL.

 

[Kev the gas]

For my trouble a box of Stella, cans not bottles :cuss:

let me know.

Kev.

 

[Dannypipe]

Well thanks very much Kev. Please put my name to it. Looks like I'll be driving out to your place again! I will come loaded with a a few crates of wife beater!!

 

[Dannypipe]

Just bumping this thread as I won the job and am speccing the install.

I was going to use two 15/60's as the shunt pumps. I was on ebay, looking for something else, and came across a UPS2 25-40. Which looks suspiciously like a pump from an underfloor heating manifold. It's A rated, and a good price. I called Grundfos who told me it isn't a UK pump so don't know where they got them from. It will probably do the job but they suggested I go through a merchants for warranty reasons.

I like the idea of using a pump with a bigger bore. I think I may be confused though as Grundfos said this pump doesn't have a bigger bore. Surely being a 25/40 the bore is 25mm as opposed to 15?

Anyone have any comments to make on this?

 

[julesverne]

this is a really interesting thread. i don't work on anything over 4 beds in my area. does anybody have any link to info i can read about the systems /design your discussing.

1 quick question is it ok to cascade boilers on domestic ticket as long as it its below75 kw or is this strictly in the realms of commercial.

thanks all

 

[Dannypipe]

Hi Jules. It's fine to cascade boilers up to your limit. I've cascaded oil boilers to over 80KW in the past, but that was working alongside my dad who was a commercial fitter for years. Oil didn't even have a commercial qualification until about a year or so ago. Croppie was one of if not the first one in the country to qualify for it.

By the way the limit with gas is 70KW not 75. Here's a snip lifted from Kirk a couple of years back.

~ domestic is up to 70kw appliance, or pipework up to 35mm as long as it contains a total installation volume of less than 0.035m3, a U16 meter can be used depending on overall volume not exceeding 0.035m3

 

[Dannypipe]

Now can someone comment on the pumps?! LOL

I'm having a bit of a crisis of confidence as I've worked along side my dad my whole working life, but I'm doing this one off my own back. Dad can come and help me if I want it, but I want to leave the old boy in peace! I'm sure I'll be fine, but I don't want any slip ups. I sound like I'm 20 not 35!!

 

[SafeGasInstall]

Thanks for that.

Can you explain why you have to configure the f&r's like that? To maintain an equal flow rate I'm expecting.

I'm also going to quote to fit a sequencer though looking at the other quotes, they haven't. I've installed one before and it's worked well. I used the Warm World model. In fairness it broke after two years (a relay went) but the new one has been in a couple of years now and is all good.

Sequencer ???

 

[Dannypipe]

Not fitting the sequencer, he didn't want to pay the money. I think they're great. Basically it fires one boiler if demand is low (say it's doing one zone only or the ho****er coil). Then it automatically switches with a timer which boiler is firing (so they wear evenly).

Then if the pipe stat picks up too much of a temp drop, it brings both boilers in. Saves gas, and less wear on the boilers. I've photographed the last one I fitted and put it up on here. A relay went buzzzzzzzz in it though. So had to change it last winter.

 

[SafeGasInstall]

Danny do you have a link pls
is sequenser used instead header ?

 

[Dannypipe]

Intelligent heating - Save money on your heating bills

No mate, you still need the header (depending on the system of course) other cascades don't need headers as we know.

 

[julesverne]

knew it was in the 70's not ever likely to get close to that in the area i work biggest install i've done is 35kw but it would be nice to read up on it out of interest.

Hi Jules. It's fine to cascade boilers up to your limit. I've cascaded oil boilers to over 80KW in the past, but that was working alongside my dad who was a commercial fitter for years. Oil didn't even have a commercial qualification until about a year or so ago. Croppie was one of if not the first one in the country to qualify for it.

By the way the limit with gas is 70KW not 75. Here's a snip lifted from Kirk a couple of years back.

~ domestic is up to 70kw appliance, or pipework up to 35mm as long as it contains a total installation volume of less than 0.035m3, a U16 meter can be used depending on overall volume not exceeding 0.035m3

 

[stevetheplumber]

in the days before the distinction on comercial we fitted 4 vaillants onto some 4 inch pipework via a low loss header worked fine but this was before condensing we had the header made up in welded steel

 

[Dannypipe]

I don't tend to fit many small boilers, but I don't regularly fit 60KW. Most of my stuff is between 30 and 40KW. I probably only do something like this every couple of years. I will photograph the work as it progresses and put it up on here. I'm starting on one of the out buildings first though, and changing the oil fired boiler for an 18ri.

 

[Ch4 plumbing]

I know it's a bit late to reply about the F/R pipe configuration but I've always known it as reverse return, and the reason to do it is so both boilers workload is equal, if you pipe them any old way one of the boilers will work it's self to destruction while the other idles. Hope that helps mate.

 

[Dannypipe]

I am aware of that thanks ch4 but any advise is always welcome.

 

[Killy Bing]

Why don't you wire a pipestat as a room stat to the low loss header and set it to 60?

 

[Dannypipe]

For Billy.

 

[Dannypipe]

This is the LLH I'm proposing for the install. I know the 54mm is over kill but I don't want to restrict the existing flow header on the system. Infact I don't want to alter that at all, as I know it works. I got the old boiler running. Sounds like a bag of nails, but helped with cleaning the system.

 

[Killy Bing]

Over engineer and earn a few quid less.

save a few quid and cost yourself in the long run.

no brainer on this type of install

 

[Ermintrude]

If you had coupled two logic heat only 30kw in parallel with reverse returns you could avoid LLH and only need one pump and two Aav. But it's horses for courses! For the cost of the LLH you could have a half day?