queries; low combi pressure? / cul-de-sac pipes? / combi draianage?

[skrivener]

Hi. I've just had a combi boiler fitted & rep is coming back & I feel I need to get a bit more knowledge beforehand. I'd appreciate anyone's advise on these points (yes/no would be fine on most). Thank you.

1) I've now got several 2ft 'cul-de-sac pipes" in both radiator & cold systems is this OK

2) The condensate drain on the Vaillent 28 attaches (inside) between the sink's u-bend seal & the drain, but the manual seems to illustrate it being before the u-bend. Is this OK?

3) My boiler is shutting down with 0.2bar 'call engineer' & most of the time flashing the display on 0.6-0.7bar. Is this measuring the cold water pressure entering the boiler? (which seems to quite thunder out all cold taps). Can I get some rough estimate of pressure (or bars?) by counting litres per min flow from the mains tap near the boiler? What questions should I now ask about this lack of pressure?

4) I've been left with a pipework loop in the loft where the 2 reservoir tanks used to be (It appears an original 15mm pipe is now joined to an original 25mm pipe. I got rid of the loft tanks as 15" of lagging goes up in the loft next week & I said I was worried about water freezing. I regret the flow was not discussed at the quote, but I'd rather assumed the cold water system would run from the ground floor to the 3rd floor once the tanks were removed, not from the ground up up to the 4th floor (loft) & then back to feed the taps on the way to the ground again. Is this a normal arrangement? (re the boiler pressure, it seems likely to be not on this route)

5) It's too late to do again, so its a minor quibble, but I was told it was 'just as good' to power flush the whole system after refilling rather than doing the individual radiators when the valves were being replaced & system drained. But I see forum threads here about power flushing radiators when removed. Is that best way?

Thanks

 

[diamondgas]

Hi skiviner & :welcome: to the forum

My first thoughts are how much did you pay and what potential pitfalls were explained?

1) I've now got several 2ft 'cul-de-sac pipes" in both radiator & cold systems is this OK

You'll have to expand on your description as I haven't got a clue what you mean by "cul-de-sac pipes" ... That conjures up dead ends?

2) The condensate drain on the Vaillent 28 attaches (inside) between the sink's u-bend seal & the drain, but the manual seems to illustrate it being before the u-bend. Is this OK?

Are you saying that they've tee'd in before and not after the "u-bend"? Again struggling with what you're describing. Any chance of some pictures perhaps? I'd tee in after the trap on the outlet side.

3) My boiler is shutting down with 0.2bar 'call engineer' & most of the time flashing the display on 0.6-0.7bar. Is this measuring the cold water pressure entering the boiler? (which seems to quite thunder out all cold taps). Can I get some rough estimate of pressure (or bars?) by counting litres per min flow from the mains tap near the boiler? What questions should I now ask about this lack of pressure?

The display lets you know the pressure of the water in the heating system. Nothing to do with your cold water supply or tap pressure. You'd have to read the manufacturers instructions but you'd expect the pressure to be around the 1 - 1.5Bar mark cold. And not drop idealy! However if it is having to be re-pressurised frequently it indicated that the system is leaking somewhere!!

4) I've been left with a pipework loop in the loft where the 2 reservoir tanks used to be (It appears an original 15mm pipe is now joined to an original 25mm pipe. I got rid of the loft tanks as 15" of lagging goes up in the loft next week & I said I was worried about water freezing. I regret the flow was not discussed at the quote, but I'd rather assumed the cold water system would run from the ground floor to the 3rd floor once the tanks were removed, not from the ground up up to the 4th floor (loft) & then back to feed the taps on the way to the ground again. Is this a normal arrangement? (re the boiler pressure, it seems likely to be not on this route)

Definitely something to discuss with the installers. It sounds like you may have had some of the cold supplies in the house fed from the tanks in the loft?

5) It's too late to do again, so its a minor quibble, but I was told it was 'just as good' to power flush the whole system after refilling rather than doing the individual radiators when the valves were being replaced & system drained. But I see forum threads here about power flushing radiators when removed. Is that best way?

My personal opinion is it's best to powerflush the original system before the new appliance is installed or at least to be able to lock off the new boiler so that none of the old system water is ran through it! Radiators in my opinion should then be flushed through individually, culminating in a whole system flush at the end of the process...!

Each to their own though!! From what you've mentioned my main concern would be the loosing of pressure! It sounds like some size house also over 3 floors, just curious but did they zone off any of the areas?

 

[skrivener]

Thanks diamondgas; kind of you to reply

how much did you pay and what potential pitfalls were explained?

Seemed a normal price from a largish company. It's always hard to know what questions to ask about pitfalls until after the event. It's often only then that you even see the pits. I now guess that just joining up the water tank's in-pipe to its out-pipe is probably the standard method. I should have thought of this & I'm relaxed about negotiating again on how best to get this unnecessary loop of water pipes out of the loft before the lagging goes in

what you mean by "cul-de-sac pipes" ... That conjures up dead ends?

Yes I was trying to describe dead end pipes. I guess it is OK to have very short ones, but long ones od 1 & 2 ft seem to mean that stagnant water can be trapped in the system. I was wonder if there is a maximum length allowed for a 'dead end pipe' in the cold water or heating system?

I'd tee in after the trap on the outlet side.

So that sounds fine then, Thanks. My condensation drain pipe has been attached between the sink's u-bend and the outside drain. It just seemed odd as the drains of all 4 other appliances attach to the 'house' side of the u-bend. (I bet I just misinterpreted that illustration)

It sounds like some size house also over 3 floors

Regrettably my palace is just a basic town house perching on top a garage

Thanks again for the information

Hi skiviner & :welcome: to the forum

My first thoughts are how much did you pay and what potential pitfalls were explained?



You'll have to expand on your description as I haven't got a clue


Are you saying that they've tee'd in before and not after the "u-bend"? Again struggling with what you're describing. Any chance of some pictures perhaps? I'd tee in after the trap on the outlet side.



The display lets you know the pressure of the water in the heating system. Nothing to do with your cold water supply or tap pressure. You'd have to read the manufacturers instructions but you'd expect the pressure to be around the 1 - 1.5Bar mark cold. And not drop idealy! However if it is having to be re-pressurised frequently it indicated that the system is leaking somewhere!!



Definitely something to discuss with the installers. It sounds like you may have had some of the cold supplies in the house fed from the tanks in the loft?



My personal opinion is it's best to powerflush the original system before the new appliance is installed or at least to be able to lock off the new boiler so that none of the old system water is ran through it! Radiators in my opinion should then be flushed through individually, culminating in a whole system flush at the end of the process...!

Each to their own though!! From what you've mentioned my main concern would be the loosing of pressure! It sounds like some size house also over 3 floors, just curious but did they zone off any of the areas?

 

[jtsplumbing]

Is this a large national Co that has fitted this Boiler ? as you say The rep is calling back, What make Boiler do you Have ? How meny bathroom's ? could be that a combi is not suitable for your house, from what you are saying a lot of courners have been cut, Lot of questions ask'd by Diamondgas so will not repeat them, but some Photo's would be good

 

[skrivener]

Is this a large national Co that has fitted this Boiler ? as you say The rep is calling back, What make Boiler do you Have ? How meny bathroom's ? could be that a combi is not suitable for your house, from what you are saying a lot of courners have been cut, Lot of questions ask'd by Diamondgas so will not repeat them, but some Photo's would be good

Thanks for the reply JTS
Its a largish company & a Vaillant 28. Regret the house is not a palace as 3 stories imply, just a 3 bed, 1 bath, 1 living room townhouse (11 rads) perched on top of a double length garage with a utility room on ground floor & kitchen & boiler on middle floor

Oddly I've had two tries to reply to diamondglas's questions, but neither has appeared, I'll see if this gets posted & have another go

 

[jtsplumbing]

Hi, So normal Town house ! could i ask if the people installing your boiler, fully understood what thay were doing, as some of these Co tend to employ less experianced engineers, to keep the costs down, they seem to have cut corners and not done things right , eg flushing system, removeing dead legs (Unwanted pipework) ect. Flashing light has nothing to do with your water pressure from taps, this is the pressure that needs to be in the system (Boiler/Radiators) in order to work, if pressure falls to around 0.6 bar then boiler will stop working, was you shown how to top up pressure if required ?? you need to ask about gas supply , this is quite important with combi boilers ! Did they fill in information in installation book (Log Book) this is also very important if you need to call out service engineer and for warranty on boiler, When you say rep is comeing back is this from installation Co or boiler maker ?? Also how faraway is the boiler from taps again a important factor with combi boilers.

 

[skrivener]

Thanks for taking the time to reply Diamondgas

My first thoughts are how much did you pay & what potential pitfalls were explained?

seemed a normal quote from an established company; Guess the trouble with potential pitfalls are you don't know what questions to ask until you discover the pit; "I'll take heed & try and find a leaflet on 'Potential pitfalls when getting a kitchen quote", so I ask better questions on the next round.

1) I haven't got a clue what you mean by "cul-de-sac pipes" ... That conjures up dead ends?

Another 10 years & my newly invented term reach a dictionary. Yes, I was trying & failing to describe dead end pipes. I'd guess very short dead end pipes may be fine, but assume 1-2ft long long ones means stagnant water can be in the system. I was wonder if there is any industry standards on this.

2) I'd tee in (the boiler's drain) after the trap on the outlet side.

Thanks, That's fine then. The drain does attach between the sink's U-bend & the outside drain. It was just that my 3 other appliances all attach above the u-bend, so it seemed odd. I probably misinterpreted that
illustration

3). The display lets you know the pressure of the water in the heating system

Thanks for explaining. No doubt the rep will start hunting that down when he comes. (& I'll double check for leaks tonight)

5. Sounds like you may have had some of the cold supplies in the house fed from the tanks in the loft?

Yes, seems 4 of the 5 cold taps used to run of the loft tank and the tank's in-pipe has just been joined-up to its out-pipe. I guess that's the easiest & perhaps the normal way to fit a combi? However I was trying to get rid of the freezable water from the loft, before I installing loads of loft lagging. Unless its normal to remove these water pipes from the loft along with the water tank, I guess I'll negotiate a price to have them taken out & for the mains to enter the cold water system on the ground floor. I'd rather assumed the water would simply enter the cold water system by the boiler & the system would be capped/sealed off by the top tap (the bath)

6. re poweflushing; Each to their own though!!

That's fine. I'll know next time. Though it seems a shame there's no industry powerflush standard so that people can specifying what sort of powerflush they will do. It must be hard to compete if there is no level playing field, I imagine your powerflush might take 4 times longer than others who use the same term.


Thanks again

 

[skrivener]

Hi JTS

some of these Co tend to employ less experienced engineers

Yes, but perhaps accidentally, as one of the two due to install it called-in sick
​

was you shown how to top up pressure if required

No annoyed the fitter left before I got back, despite having my number & being 5 minutes away. I'll extract a decent briefing from the rep (their contracts director)

Did they fill in information in installation book (Log Book)

Yes; thanks for that thought, I do have a commissioning checklist, I'll ask for it to be explained as gas inlet pressure (19mbar) recorded but no boiler pressure. I'll make sure the "satisfactory demonstrated" section is properly completed when the installation rep calls)

How faraway is the boiler from taps again a important factor with combi boilers

Hopefully no big problems there, it's by the kitchen sink on middle floor with just a bathroom directly above & utility & toilet sink below on ground floor

 

[diamondgas]

Regards (5) skrivner ... Is there no where lower down where these two pipes could have been joined? Usually, but not always, you run the pipes rising and falling from the same place eg. airing cupboard or the likes? If they do come down in the same place it would be worth having them connected below the ceiling rather than in the loft... Could well have been done for convenience or laziness or the only way?

 

[jtsplumbing]

Ok just make sure that all the information in the commissioning list as been fill'd in, not just gas pressure, also need gas rate on both heating and hot water, should have engineers name and gas safe number, hot water temp & flow rate. Hope you get it sorted, but need to ask about length of pipe runs for hot water you need to keep these as short as possable,

 

[skrivener]

Ok Thanks for your help guys. I'll make sure I get those details added. Your help much appreciated.