Ecotec plus 837 gas inlet 22mm

[africadan]

Just had a boiler installed today, Im concerned that he has connected the wrong size gas inlet pipe.

From the gas he has connected a 15mm pipe, then 1m from the boiler he has enlarged the 15mm to a 22mm pipe so that goes into the boiler.
The cooker is also connected to that original 15mm pipe.

Should he have connected 22mm for all the pipe?? should there really be a T junction to the cooker sharing the same pipe as the boiler??

Thanks for any help.

Dan

 

[corgiman]

if the boilers instruction state that a minimum of 22mm gas supply should be connected to boiler (gas4you will know he is our resident vaillant nut) then he has cocked up royally

if he has undersized the pipe (does your hob burners flame dip when the boiler comes on?) then he has cocked up royally

methinks we should call your installer sire

 

[fitz1]

whose fitting boilers on sundays.

 

[corgiman]

he must be keen fitz

Mind you I repaired seven old ones today

I am so great I am



NOT i am a fool should have been at home wif me feet up

 

[timbalcombe]

I have 22mm to my vaillant ecotec pro and my hob dips!
15mm to the hob, which come off the same inlet pipe on a T

I rang vaillant tech office who said 15mm will be fine, but every quote I had said I'd need to convert to 22mm.

I'm no expert but I'm sure it says in my install manual a run of 15mm from the boiler of 1m is acceptable. I'll have a look and post back.

 

[gas4you]

837 MUST have a 22mm gas supply to it. If running cooker off same supply then no more than 6M of 22mm copper must be used, if further then it should have been changed to 28mm from gas meter to 6M before boiler. (all lentghs 'equivalent lengths')

I've just fitted the same today. When on dhw the 837 will use 4m3/hr gas rate and cooker allowance would be around 1m3/hr. Nearly the maximum for a domestic meter!

 

[corgiman]

837 MUST have a 22mm gas supply to it. If running cooker off same supply then no more than 6M of 22mm copper must be used, if further then it should have been changed to 28mm from gas meter to 6M before boiler. (all lentghs 'equivalent lengths')

I've just fitted the same today. When on dhw the 837 will use 4m3/hr gas rate and cooker allowance would be around 1m3/hr. Nearly the maximum for a domestic meter!

see told ya

 

[Agile]

The test is what pressure loss is measured between the meter and the boiler.

This must not exceed 1 mB !!! That would never cause a gas hob flame to dip !

Anyone with more than this can complain to CORGI and they will attend and serve a defects notice on the installer and he must correct that at his own expense.

I dont agree with the pipe sizes quoted by Gas4you as they look too small. I have asked to see his calculations or an address where I can measure the performance but I am still waiting.

Tony

 

[gas4you]

Tony

Where and when have you asked for my calculations and are still waiting on me? certainly not on here and I have received no e-mail from you!

My general calculations based upon the 837 using the M I's stated 4m/3 /hr and an average gas cooker using 1m3/hr and using the Corgi book pipe sizing table.

Total gas use = 5m3/hr 6 metres of 22mm copper will give 1mbar pressure drop for a maximum of 5.8m3/hr and 28mm copper could in theory be used up to 20m (will allow 5.9m3/hr)

The figures quoted in my response to the op was mainly to point out the inadequacy of his pipes installed by his fitter and taken as a general point rather than a precise calculation intended for his own use

All M I's, whatever manufacturer all state that you should never reduce the gas pipe size to less that the size that they supply as a connection to their appliance.

As for the one I had just installed I had the same gas rate needed, limited my 22mm copper to 3m and had the remaining 5m in 28mm, all equivalent lengths. This gave me the required 0.5 mbar pressure drop to each appliance, totaling the 1mbar drop allowed. In theory by the CORGI book

If we can't trust our great mentors for supplying accurate info for us to work with then who can we trust

 

[Agile]

No, it was not your 6 m of 22 mm that bothered me so much but that you implied adding lengths of 28 mm could be done without reducing the length of 22 mm.

Whilst we know what "equivalent length" means, most DIYers dont. They are likely to read that as "up to 6 m of 22 mm is acceptable".

I would prefer to say that with a high power boiler unless the distance to the meter is less than 3-4m its likely to need at least 28 mm.

There is another problem and that is the measured resistance is always considerably higher than whats calculated. I allow 20% but Chris says his experience is that 70% is often more realistic.

One reason for this discrepancy is that the tube is usually cut with a pipeslice and that gives a narrowing in and out of the joint. For DIYers you have to understand that each elbow or other change of direction adds about 0.5-1.0 m of equivalent pipe length as a result of the increased resistance.

Tony

 

[Gasguru]

Just been to a Greenstar Junior. This consumes 2.59 m3/hr. The drop was a tad over 1 mbar. The pipe run was 9.5 m of 22mm with 6 soldered elbows (ie another 3m) so an equivelent lenght of 12.5m. The tables suggest nearly 25m lenght should be acceptable with this flowrate.

I suspect a significant proportion of the loss is through the boiler isolating valve, gas pipework internal to the boiler before the gas valve and the gas inlet filter. And further loss as Tony says is due to the use of a pipeslice. The tables were written when pipes were cut with cutters that did not narrow the pipe significantly.

 

[gas4you]

So are we back to calculated losses then guess the rest. There is a great difference, Tony, between your extra 20% and ChrisR's 70%.

So how can we make sure before fitting?

 

[Gasguru]

Run in all in 35mm

May not seem so crazy either - the way the utilities are going pressures aren't necessarily going to be maintained at 21 +-2.

 

[gas4you]

Think i'll buy shares in Yorkshire copper tube

 

[Agile]

Tony

Where and when have you asked for my calculations and are still waiting on me? certainly not on here and I have received no e-mail from you!

//www.diynot.com/forums/viewtopic.php?t=80386&postdays=0&postorder=asc&start=45

Do you check the pressure loss on your installations at full power?

Tony