LPG Discussion Forum

hi all im having a bit of a problem with my lpg as when i turn the heating temp down the gas cuts off any help much appreciated

Sounds like you need to look where the coolant pipes have been intercepted to feed the vapouriser, The Vapouriser needs a good supply of hot coolant to keep it from freezing. Most likely you have a valve that shuts off the coolant flow through the heater matrix when the heater is set to cold, and that valve is also stopping your flow through the vapouriser.

thanks for the reply brian it lookslike they areonto the 2 pipes coming from the aux pump going into the matrix but i dont know where they should be if that makes any sense

If they (or at least the one on the flow side) aren't hot with the heater off, then no. Simon or someone else may be able to point you to the best location for them, but you need something that stays the same temperature as the coolant with the heater on hot or cold either way.

I'd guess your aux pump maybe doesn't run with the heater on cold, someone will reply with the best position to use hopefully.

ive tried to work it out too, to me its just pipes going everywhere and i really dont understand how it works thanks again brian

You can post photos on here (use the full editor and preview button to post a reply to see it). That might help to see what you might do to sort it out.

If you can locate the vapouriser which it sounds like you have, there will be two pipes running to the coolant system. Set the heater to cold, and see what temperature the pipes are after a few minutes. The described behaveour suggests they will be cold, its a case of finding somewhere where they are not cold in that state (but needs to be somewhere suitable for a supply at the same time).

When you reduce the pressure of lpg (which is what the vapouriser is doing, to turn it from a high pressure liquid to a low pressure gas) it requires heat to do so (or will draw in heat as part of the process, making the vapouriser cold). You feed it with coolant to keep it warm enough to prevent it freezing (as if it does that, it won't be able to accurately control the pressure as the rubber bits get much too stiff inside it, and can damage it). If its switching back, its suggesting its getting too cold, the lower temp limit is usually quite cold as its mainly there to prevent damage to the unit.

From the L322 workshop manual

Good idea, should have thought of that! So if the OP can identify where the lines are currently connected to, then that should make it possible to work out where it should go.

As in the pic, on L322's one pipe from the engine is common to both matrix's and goes straight to the firewall, the other pipe from the engine goes to a double solenoid block on the passenger side inner wing, from the solenoid block a pipe runs to each of the two matrix's.

The reducer has to be plumbed in parallel - connected to the pipe that runs straight between the engine and firewall common to both matrix's and to the pipe that runs between the engine and the solenoid block.

If the reducer is plumbed in series or is plumbed in parallel but connected to a pipe between the solenoid block and one of the matrix's the reducer won't get a flow of water when the heater is turned off or set to a cold temperature.

i think im getting it sorry for being so thick,mines is teed off pipe 5 and 3 would that be my problem then

i think im getting it sorry for being so thick,mines is teed off pipe 5 and 3 would that be my problem, then so it should be on pipes 1 and 2 on the diagram

Either 3 or 5 (whichever of the two gets warm with the heater off - 3 I think more likely?) and 7 I think is what you actually want (7 being the return to the engine). I can't work out

You don't want the ones on the FBH (Fuel Burning Heater) as that probabbly only gets hot when its cold outside (would be your extra heater of some description, don't know on the l322 what conditions that would operate under).

2 Pipes connect to the engine, simply T into both of those 2 pipes.

At the firewall there are 3 water connections, a common for both matrix's and a separate pipe for each matrix.

One of the pipes from the engine runs directly to the firewall common pipe, T into that.

The other pipe from the engine runs to the solenoids, T into that (3 pipes run to the solenoids, 2 run to the matrix's, only one runs to the engine).

brian,lpgc,gilbertd thank you all very much the penny finally dropped sorry for the stupidity i will put a picture up once i do it just to be sure thanks again

I'm still not that clear personally so I can understand the confusion. If Simon had said Tee into pipes 6 and 7 (or whatever) it would have made far more sense. Unlike the diagram for the P38, that one doesn't have arrows showing which way the coolant flows so isn't as clear as it could be.

hi G i looked up the coloured diagram under l322 coolant system and there is another one im sure on the same page shows the flow. Im saying ive got it but i havent done it yet lol i believe im going to be using pipe 7 and 2 on the diagram above i think

7 and 2 seem to be correct. The diagram is arguably more confusing to look at than the setup itself, when you look at the engine it's obvious which 2 pipes run directly to it.

It doesn't really matter which way the water runs if the reducer is mounted low enough and it's bled up but there are ways of finding out which way water runs, sometimes it's quite obvious, if say one heater circuit pipe connects near the rad top hose and other heater circuit pipe connects near the rad bottom hose the one near the top hose will be the output.

I was probably thinking more BMW X5 than L322 in my earlier post but the systems are very similar, it still holds true about having to avoid plumbing to the wrong side of the heater circuit solenoids or an auxiliary pump and T'ing into pipes that lead directly to the engine's heater water circuit.

spot on lpgc just finished it cool air temp good and the gas is coming on within half a mile thanks again i really appreciate all your help,basically if your plumbing gas in stay in front of the aux pump and its bits and bobs thanks again Just a we quick one for your infinite wisdom is there another guage that can be used on the prins vsi mines is saying constantly full

It may not be a case of another gauge, but setting up the one you have. It might help to know what you have fitted as well (type of gauge or type of tank, as a single hole uses different sensor to a 4 hole tank).

Does the reading you have change at all or stay the same all the time?

not really sure mate its a prins kit with the tank in the spare wheelwell and the guage stays full all the time