Connecting an LPG boiler to natural gas

[Oldmanfrank]

Hello all, i have been advised that this is a question for a Mr Tony Agile.
What would happen if a central heating boiler specifically designed to operate on LPG gas was connected to a natural gas supply. I imagine if a Natural gas boiler was connected to an LPG supply it wouldn't withstand the higher gas pressure of the LPG without chaging the injectors. Was wondering what would happen if an the LPG boiler was connected to natural gas though?
Regards Frank.

 

[doitall]

It wouldn't work, unless you can boost the gas to 37 m/bar

 

[Oldmanfrank]

I disagree, what brings you to the conclusion that it wouldn't work?
All components would operate as with natural gas the only dfferance would be in the combustion of the gas in my opinion. Possibly not enough heat output.

 

[namsag]

All depends what boiler , some only need the injectors changed others need several bits doing,

You may find the injector holes would be that small it would not allow enough gas out for minimum firing pressures to be reached for proper ignition, allowing boiler to fill with gas and possibly go BANG when it did light

 

[mickyg]

it might work it might not! you'd get incomplete combustion, which could result in a t/couple not holding or a flame not rectifying on a direct ignition boiler. Ultimately if it did stay alight it would cause sooting and possibly your early demise!
Why is this a question for Tony??

 

[gremlin16]

Not a problem if you ad a Broag Remeha Avant
(Except the 39c)

Just reset the parameters and a slight tweak on gas valve and your in business

 

[gas4you]

It wouldn't work. If an atmospheric burner then you will probably only get about 25-50% of the burner alight.

 

[Oldmanfrank]

Just wondering as i have seen that worcester and vaillant both produce boilers which have LPG in there title and seem to be identical in every way to the nat gas versions. Why is this, and what if any are the physical differances?

 

[kevindgas]

sorry but it does work
went to a house in thetford a few years ago to do a landlords check.

i found the gas meter did all the usual checks - all ok no leaks, bonding ok etc

went in to kitchen: OMFG!!

double oven in a carcass look at this first, notice straight away that the air grill between the 2 ovens has melted? thinking to myself why's that happened? so i light the main oven flame is reaching the top of the oven approx 9" flame! shut that off and check the top oven flame about 6" high swap over to grill flames flopping all over the place all 3 bright orange.

go to hob next again flames are orange and all over the place.

condemned the whole house at this point.

so i start to investigate oven take it out and look at rating plate can only find G37 details so phone up new world who confirm it is a LPG only unit and can't be adapted

after a lot of questioning it transpired that yes the house had been converted from LPG to NG about a year before!

 

[muggles]

sorry but it does work
went to a house in thetford a few years ago to do a landlords check.

i found the gas meter did all the usual checks - all ok no leaks, bonding ok etc

went in to kitchen: OMFG!!

double oven in a carcass look at this first, notice straight away that the air grill between the 2 ovens has melted? thinking to myself why's that happened? so i light the main oven flame is reaching the top of the oven approx 9" flame! shut that off and check the top oven flame about 6" high swap over to grill flames flopping all over the place all 3 bright orange.

go to hob next again flames are orange and all over the place.

condemned the whole house at this point.

so i start to investigate oven take it out and look at rating plate can only find G37 details so phone up new world who confirm it is a LPG only unit and can't be adapted

after a lot of questioning it transpired that yes the house had been converted from LPG to NG about a year before!

I wouldn't really call that 'working'. Burning, yes, but not really working

 

[Agile]

I dont know why my name should be mentioned.

Coincidentally, I had a call tonight from a caravan park resident with an LPG supply and a new boiler which has not been properly set up for LPG by the installer!

In most cases, with a conventional burner, the supply pressure will be 20 mB instead of 37 mB so the heat output will be about half or less of the expected value.

In most cases new ( larger ) injectors are needed and the gas valve ( and sometimes the electronics as well ) have to be readjusted. Not a big problem for someone who knows a bit about gas.

Now the horror story! Many years ago I took a NG two burner Baby Belling cooker unit to France to operate off the LPG. I had to reduce the size of the injectors by flowing a little solder through the jets to reduce their size. Its still in use today about 30 years later! I wasn't CORGI registered then and anyway they dont operate in France unless I invite them to my cottage!

But its always better for the job to be done properly by someone who knows about gas. I have heard of people buying LPG boilers cheaply on Ebay because they were wrongly purchased and then selling them again to people who expect to use them on NG. The reality is that all boilers are designed for NG and then modified to work on LPG.

Tony

 

[Slugbabydotcom]

What would happen if a central heating boiler specifically designed to operate on LPG gas was connected to a natural gas supply.

According to the Gas Industry Unsafe Situations Procedure

Not suitable for use with gas supplied

Immediately Dangerous and RIDDOR reportable

 

[Aquaheat]

I disagree, what brings you to the conclusion that it wouldn't work?
All components would operate as with natural gas the only dfferance would be in the combustion of the gas in my opinion. Possibly not enough heat output.

WOW!! what a statement to make considering one post previously you needed help!

By running a boiler on a gas that it isn't built for is extremely dangerous and with a comment like that i doubt that you are competant to carry out an LPG conversion anyway.

I disagree with your entire thought process and am guessing that you have already done this and you are trying to find out why it won't work and how much longer you have to live!!

My only advice to you is that now you have converted it, when it goes bang your safe to duck!!!!!

Mmmmmm money versus lives???? decisions decisions!!!

 

[gas4you]

Vaillants have to be set for LPG/NG with an FGA

 

[kevindgas]

I wouldn't really call that 'working'. Burning, yes, but not really working

defining working for most people - its working / its not working
defining working for pedantic people its working properly / its not working properly / its not working at all!