Microbore balancing

[bilco_21]

Hi all,
I live in a 3 bedroom semi detatched new build house with a sealed system, condensing boiler ( ideal icos he15) and 10mm microbore plastic heating pipe system.
I was wondering wether or not this requires balancing as our friends who live in a house identical to ours their heating system has every single radiator lockshield valve fully open on all Rads.
Our heating system has the pump on speed 3 (myson CP53) Auto bypass valve on 1.5 (honeywell DU145) and the rads are fully open downstairs and about half open upstairs. However after many hours of reading info on the net i wonder wether the system is set up correctly as i know only to well what new builds by persimmon are like and the fact that our friends house is completely different set up to ours. I wonder wether our pump speed is too high and if our rads need to be finely balanced as i have heard that microbore is nearly self balancing or wether i should open the lock shields fully like our friends. I also wonder about the auto bypass valve is it too lower a setting??? Any help is very much appreciated, Many thanks Will

 

[Dotty]

Do all your rads heat up at roughly the same time? You don't actually say whether you've a problem or not.

 

[mountainman]

In other words, if it ain't broke don't fix it!

 

[bilco_21]

Hi sorry I didn't actually put why I was asking I just wanted to ensure that my system was correctly setup and running as efficiently as it should be after my experience with "persimmon cowboys"!! I thought I would just ask the professionals opinion on how it should be setup.

 

[mountainman]

In reality, if you are happy with the performance then leave well alone.

 

[SimonJohns]

In other words, if it ain't broke don't fix it!

Ditto

10mm is not self Balacing but if it works it works.

I can't see you saving much with a perfect balance

 

[tamz]

Rather than worrying about the set up you should worry about the lifespan of your boiler. Best start sticking some money in a jam jar for when the time comes.

 

[bilco_21]

Ha yes I have read many a negative comment about the ideal boilers lol! It can only be a matter of time I guess?!?!! Ok if you guys think it's all sounds ok and like you say if it works leave it that sounds good to me!! I appreciate your help guys!

 

[tamz]

Maybe your bypass needs setting a bit better. 1 1/2 is too low for the pump setting you have.
This will tell you how to set it if you have a spare half hour
http://www.honeywelluk.com/Documents/Full-Install/pdf/951.pdf

Otherwise don't worry about things

 

[bilco_21]

Cheers tamz thanks for the info on setting the bypass. I've hunted through my boiler installation instructions and also all the available literature on the ideal website but can't seem to find the minimum flow rate through the boiler, would anyone have any idea what it would be for an Ideal icos HE15?

 

[DirksPlumbing]

Ditto

10mm is not self Balacing but if it works it works.

I can't see you saving much with a perfect balance

That is to true to be good. 10mm plastic has roughly 6mm internal bore which is insufficient for most radiator sizes anyway. Then stick an insert at some manufacturer that is 4mm internal only. Feeding for example a 1200x600 K2.
This is a bit like shoving a full pig in your fridge. If you just heat it enough it will fit.
Wonder how some expect to run the boiler in condensing range without running enough water through the boiler. Pump has to run like mad to make good for that. But at least one wins, your energy supplier.

I would very much say if the system works be happy. Throttling the flow even more will definitely not make your boiler more efficient.

The self balancing story comes from the fact that the volume of water can not move because of the high internal resistance which leads to a pressure build up. This high resistance in the pipe work in conjunction with the raised pressure means that the differences in internal resistance of the radiators have barely any influence on the flow anymore.

 

[DirksPlumbing]

I've hunted through my boiler installation instructions and also all the available literature on the ideal website but can't seem to find the minimum flow rate through the boiler, would anyone have any idea what it would be for an Ideal icos HE15?

What delta K you try to achieve?
For example 10 K spread at 8.8kW asks for a volume stream of nearly 1000l/h.

Edit: Ooops I think you are asking for a minimum safe rate of water exchange in order to allow the sensors to be streamed at.

 

[bilco_21]

Hi dirksplumbing thanks for your help mate. I understand where your coming from as in balancing that you don't wanna be restricting the flow even more due to the small ID of the pipe. With regards to your second post I was looking for the minimum flow rate required by the boiler itself as needed on the Honeywell instructions of the auto bypass to set it correctly. I can find the myson pump curves that I need but I just can't find the boiler min flow rate in any instructions or anywhere!! Cheers mate

 

[doitmyself]

Cheers tamz thanks for the info on setting the bypass. I've hunted through my boiler installation instructions and also all the available literature on the ideal website but can't seem to find the minimum flow rate through the boiler, would anyone have any idea what it would be for an Ideal icos HE15?

It's there - but not easy to find!

Page 10 of the Installation Manual says (Frame 3):

A suitable pump is a domestic circulator capable of providing a maximum 11oC (20°F) temperature differential across the boiler with the whole of the heating circuit open (e.g. Grundfos UPS 15/50, 15/60 or equivalent). With the minimum flow circuit allowed by the controls the differential must not exceed 25°C. (18°C for the HE15)

So at minimum output (8.8kW) the max differential for an HE15 is 18°C. The flow rate will therefore be 8.8/(4.18 x 18) = 0.12 litres/sec = 7.02 l/min = 421 l/hr = 0.42m³/hr.

As for the correct setting of the DU145, 1.5 is much too low; it should be 4 or even higher. Feel the pipe leaving the DU145 (arrow shows flow) about a foot away from valve. Most of the time it should be cold as the valve is closed and only opens when rads close down. If it is hot all the time, the valve needs to be on a higher setting.

 

[AWheating]

i suppose it could be good news that whoever commissioned your heating actually balanced it and its morely like it was commissioned and flushed correcty compared to one that has not been balanced?? who knows..........

 

[bilco_21]

Cheers doitmyself that helps me loads!! I've checked the pipe after the valve about 8" away from the valve coz it then disappears into the airing cupboard floor, and it is rather hot so that says to me that it needs to be higher. I've worked it out using your calculations on the Honeywell instructions and it says the valve should be about 4.5 on their graph. Best I get adjusting I reckon!
AW heating, I'm defo sure it wasn't balanced or commissioned as when we moved in we went to turn the heating on and nothing happened, after having persimmon contractors back it was later found that thermostat was incorrectly wired up in the junction box in the airing cupboard. This is why I have no confidence in any of the settings of our heating system because they can't have run it up to balance it or anything.

 

[AWheating]

have they filled out the benchmark cert in the boiler manual?

 

[bilco_21]

Nope I have it and it's Blank I've spoken to the installers but they assured me that I would have a completed version of it apparently I have just misss placed it according to their manager, who is an absolute wolly

 

[REDSAW]

if they havnt done it then they havnt done it..!!!

 

[AWheating]

do you have a building compliance certificate?

 

[DirksPlumbing]

Nope I have it and it's Blank I've spoken to the installers but they assured me that I would have a completed version of it apparently I have just misss placed it according to their manager, who is an absolute wolly

It is no problem that you have misplaced it. As they will surely be able to give you a copy of the misplaced benchmark document. As they have to proof they have done it and that only works by keeping a copy themselves.

 

[mountainman]

It is no problem that you have misplaced it. As they will surely be able to give you a copy of the misplaced benchmark document. As they have to proof they have done it and that only works by keeping a copy themselves.

It's probably in their office next to the pack of flying bacon!

 

[DirksPlumbing]

It's there - but not easy to find!

So at minimum output (8.8kW) the max differential for an HE15 is 18°C. The flow rate will therefore be 8.8/(4.18 x 18) = 0.12 litres/sec = 7.02 l/min = 421 l/hr = 0.42m³/hr.

As for the correct setting of the DU145, 1.5 is much too low; it should be 4 or even higher. Feel the pipe leaving the DU145 (arrow shows flow) about a foot away from valve. Most of the time it should be cold as the valve is closed and only opens when rads close down. If it is hot all the time, the valve needs to be on a higher setting.

Well spotted, I am too lazy for doing all the maths. Using the Danfoss slider I get 420l/h so your calculation must be spot on.

 

[bilco_21]

Do you think that I should demand a completed certificate! If not how could u take it further???

 

[DirksPlumbing]

I would ask for a copy. Because you can produce the empty commissioning sheet. So it is their turn to dig up the copy. And for no other reason they would have filled that in on a separate form but to copy it and issue it back to you.
Self certification obviously means that there must be a certificate.
The only reason for the absence of such a certificate would be, as AWheating stated already, a building compliance certificate.
I love them. I had a call out to a boiler roughly a year after the blocks started to get occupied. This flat had only been in use for a month.
And the tenant was unhappy about his hot water.
Frankly there was none. Reason revealed quickly as hot and cold water exchanged. And it still had a certificate issued despite the fact this boiler could not in a million years have been benchmarked or tested in another way. But still certified.
IMHO they should do away with this heavily abused undermining of the regulations. These should apply to everyone. As they have good reasons.

Does actually someone know how long those certificates have to be kept?