Vaillant ecotec plus 835 low gas pressure.

[sammathias]

Fitted an ecotec plus 835 yesterday and was only getting 15.5mb working pressure at the gas valve. WP at the meter was 19.5mb. puzzled because there is 9m of 28mm pipe and 4m of 22mm before a stub of 15mm. Gas rate of appliance was within tolerance....15.5mb is also within tolerance but too low for my liking. does anyone know what the pressure loses between gas iso and gas valve is on this appliance?
I was commissioning this at 6pm weather that makes any difference. anyway i spatt the dummy out and will return tomorrow to assess the situation and ring vaillant for their opinion. Anyone got an idea?

 

[sammathias]

Gas rate 3.61m3/h

 

[ShaunCorbs]

Don't suppose you tested before the gas valve think vaillint have a 3-4mb drop through the gas valve

 

[sammathias]

Don't suppose you tested before the gas valve think vaillint have a 3-4mb drop through the gas valve

No didnt fit a test point before the gas valve. if that is the case then its tolerable. just seems too low. i also dont understand why vaillants dont have full bore iso vlaves...surely that is restricting!

 

[ShaunCorbs]

No didnt fit a test point before the gas valve. if that is the case then its tolerable. just seems too low. i also dont understand why vaillants dont have full bore iso vlaves...surely that is restricting!

Always put one in before it enters the boiler

 

[Vee]

Gas Safe Bulletin TB 129 tells you exactly that.

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[Last Plumber]

Fitted an ecotec plus 835 yesterday and was only getting 15.5mb working pressure at the gas valve. WP at the meter was 19.5mb. puzzled because there is 9m of 28mm pipe and 4m of 22mm before a stub of 15mm. Gas rate of appliance was within tolerance....15.5mb is also within tolerance but too low for my liking. does anyone know what the pressure loses between gas iso and gas valve is on this appliance?
I was commissioning this at 6pm weather that makes any difference. anyway i spatt the dummy out and will return tomorrow to assess the situation and ring vaillant for their opinion. Anyone got an idea?

Normally around 3 mbar ish.

Take the flex off the Gas valve inside the Boiler and look at the filter/strainer to check it's clear.

If it is, and it doesn't effect any other appliances when on P1, I wouldn't worry.

 

[sammathias]

Normally around 3 mbar ish.

Take the flex off the Gas valve inside the Boiler and look at the filter/strainer to check it's clear.

If it is, and it doesn't effect any other appliances when on P1, I wouldn't worry.

Virtually word for word what the tutor said today on a vaillant course i attended in bristol!

 

[masons]

no need to worry your allowed 13mb on the gas valve

 

[Leo21]

The instructions used to give an acceptable level at the gas valve. Around 13 mbar from memory. These always read low, they have negative pressure on the u gauge for some unknown reason.

 

[Last Plumber]

The instructions used to give an acceptable level at the gas valve. Around 13 mbar from memory. These always read low, they have negative pressure on the u gauge for some unknown reason.

What do you mean?

 

[Leo21]

You don't get a true reading on your gauge. There's a small amount of suction that affects the gauge reading. It's do with it being asperated.

 

[Last Plumber]

You don't get a true reading on your gauge. There's a small amount of suction that affects the gauge reading. It's do with it being asperated.

Once the solenoid valve opens the Gas supply pressure should be enough to supply 16/17 mb at the Gas valve.

 

[Leo21]

Not what it says in m/I,s

 

[Last Plumber]

Not what it says in m/I,s

Probably not but the MI's change every 5 minutes. They used to say 20 mb. Then they said 17mb I've seen a 16 and heard a 14.

Fact is they will run safely at 14. (as long as you log the reason and it is beyond your control). There are other factors involved in the Gas pressures that MI's have in them.

It was the negative pressure on the u gauge and the unknown reason.
I didn't follow what you meant by unknown reason.