LPG home heating - Keeping bottles warm

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WanaGo

149 posts

Master Geek

#177031 19-Jul-2015 20:23

Hi All,

Recently got a central heating boiler for our house for raidators - working great.
However on cold nights the LPG gets slugglish and it switches over to the full bottle, leaving quite a lot of gas still in the 'empty' one.

One thing I have done the other day, is pour hot tap water around the bottom half of the bottle, and you can hear the liquid boiling into gas, and it gets it going for another 30mins or so, however its not really ideal to do that continuously.

I have seen in the US these bottle warmers, which are like an electric blanket for your LPG cylinders.
No use having LPG that doesnt want to come out, when they are there for the purpose of heating your house when the weather is cold.

I was just wondering if anyone knew if these types of things were legal for NZ.
I know when you get LPG installed, you have this exclusion zone around the bottle, and I wondered if this would then violate it and be illegal to use this concept here.

Just trying to find out what people do - as there are thousands and thousands of people in NZ who use LPG for heating, and many of them down south - so there must be known tricks which get around this.

Would love to hear

Regards
WanaGo

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3885 posts

Uber Geek

#1347359 19-Jul-2015 21:01

Saw a plastic box like thing in the plumbers journal that half covers the bottles and has the flue gases from a gas central heater piped into it. The leftover heat keeps the bottles warm. Only problem was it was a concept design. So don't know if it got approved. And if it went into production.

Ask your gas fitter if you can go to a 4 bottle setup. Meaning the load is spread over 2 bottles instead of 1. You will need a location test certificate. And some gas companies charge more rental fees. But last time I checked Elgas charge the same fee for both 2 and 4 bottles.

Also ask if your gas company has alpine lpg avilable. It is pure propane instead of a propane butane mix. As butane boils at around 1 deg. While propane boils at negative 68deg.

WanaGo

149 posts

Master Geek

#1347482 20-Jul-2015 09:30

Thanks.
Our bottles are about 10m away from the boiler, so cant really use that concept anyway.
We could go with 4 bottles, but I would hope there is another solution.
Propane only vs LPG would probably be better, but yeah not sure if its available on the standard bottle delivery services. Would have to retune the boiler too.

Got sick of going outside with warm water to warm up the bottle yesterday, so just ran the garden hose against it and that seemed to do the trick. But again, still not an ideal situation.
Got a new bottle delivered this morning so shouldnt have issues for another week or so. But still wanting to find out if anyone has solutions for keeping their bottles warm - legal ones would be preferred, but happy to hear about anything.

Regards
WanaGo

graemeh

2078 posts

Uber Geek

#1347496 20-Jul-2015 09:49

I heard that some suppliers weigh the "empty" bottles when they saw them and give you a credit for any unused gas. This is not an ideal solution but may be a practical one.

I assume you have already asked your current supplier for their advice.

WanaGo

149 posts

Master Geek

#1347540 20-Jul-2015 10:19

I am with Contact/Rockgas. I have emailed them asking a bunch of questions, just waiting for the reply.

I don't believe any suppliers weigh the bottles and give you credit. Not that I am aware of anyway.... Who does this, do you know?

Elgas does the bottle fills with their truck, so you only pay for what they top up the in the bottle, but our driveway is not suited for the truck, and they said they could not deliver here due to safety, so we had to go with a swap bottle system instead.

graemeh

2078 posts

Uber Geek

#1347566 20-Jul-2015 10:27

I think it was Elgas and I must have misunderstood how they worked. Hopefully Contact have a solution.

Oblivian

7297 posts

Uber Geek

ID Verified

#1347580 20-Jul-2015 10:46

WanaGo: I am with Contact/Rockgas. I have emailed them asking a bunch of questions, just waiting for the reply.

I don't believe any suppliers weigh the bottles and give you credit. Not that I am aware of anyway.... Who does this, do you know?

Elgas does the bottle fills with their truck, so you only pay for what they top up the in the bottle, but our driveway is not suited for the truck, and they said they could not deliver here due to safety, so we had to go with a swap bottle system instead.

The ones that like to keep customers :)

Most should be running the same barcode system that do delivery/collect. And they are, as pointed out assigned full to the house they are dropped to at time of delivery. And your empties are scanned for pickup, married up and the difference calculated the next fill.

WanaGo

149 posts

Master Geek

#1347590 20-Jul-2015 11:06

OK - will be very interested to see what the bills comes back with then. Only had the initial 2 bottles delivered, and today was the first swap.

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Perthman

33 posts

Geek

#1347801 20-Jul-2015 15:33

WanaGo: I am with Contact/Rockgas. I have emailed them asking a bunch of questions, just waiting for the reply.

I don't believe any suppliers weigh the bottles and give you credit. Not that I am aware of anyway.... Who does this, do you know?.

We are with Contact/Rockgas and Rockgas do check the bottles on return. I have had credits with the last two deliveries. And with the last two bottles I have noticed the red empty flag come up and deliberately left the bottle on - even to the extent of turning off the new bottle so there was a need to "suck" out of the "empty" bottle. Did this during the day when we were using gas for cooking. (We use gas for cooking/hotwater and a heater) However I came to grief one morning when I forgot to turn the new - full - bottle back on - and the water started getting colder in the shower ...which aint fun in the colder mainland.
I held off ten days after the red changeover flag came back, but even then I noticed a credit on the account. This problem only happens in the cold weatherf and is one of the reasons we went for a diesel heater in the bus....
A heater is an interesting idea, but I'm really not sure how practical it is - particularly where out bottles are located.

WanaGo

149 posts

Master Geek

#1347802 20-Jul-2015 15:39

Ok that is great news, thank you.
I hope Contact/Rockgas does the same up here.

These are the warmers I saw. Not 100% practical, no, and I have no idea if they are legal here either.... electrical near gas, etc.
Not exactly cheap either, but wouldn't be hard to fabricate, if they were legal for NZ.
These ones warm the bottles up quite a bit. In reality though you only need to take them a bit above boiling point of the liquid. So even 10-15 degrees may be OK.

http://www.powerblanket.com/propane-tank-heater/

Anyway, food for thought.
Will wait for this first bill.

Regards
WanaGo

Niel

3267 posts

Uber Geek

Trusted

#1347840 20-Jul-2015 17:31

When our church aircon failed we used a gas "jet engine" heater. It was a high pressure model and initially we had only 9kg cylinders to work with until we got delivery organized. The 9kg cylinders would freeze up quickly when below about half, but a trick that one of the guys did was to put the cylinder in a bucket of water because water has such a high specific energy. It will be hard(er) doing it with a large cylinder, and having it in water all the time might cause it to rust (if it is scratched), but maybe a fountain pump circulating water over the cylinder while in use might work?

You can never have enough Volvos!

Perthman

33 posts

Geek

#1347898 20-Jul-2015 17:50

, but maybe a fountain pump circulating water over the cylinder while in use might work?

Ummm, good idea if you were in Wairakei and had a supply of hot water out of the ground, but down in the South it would ice up and self defeat the concept!! Its realy only at this time of the year there is a problem.

Niel

3267 posts

Uber Geek

Trusted

#1347947 20-Jul-2015 19:17

Okay, the water pump would have worked if ambient was above freezing. Below freezing I think you have no chance of doing this without either running the tap or adding a heater or using multiple cylinders.

You can never have enough Volvos!

WanaGo

149 posts

Master Geek

#1348062 20-Jul-2015 22:28

Running hose works too, but not exactly a solution. End up with a boggy mess or a nice ice slide down the concrete path in the morning.

SepticSceptic

2187 posts

Uber Geek

Trusted

#1348359 21-Jul-2015 14:02

An old electric blanket wrapped around the cylinder ? Probably not for outdoor use though.

Perhaps you could rewire the heating cords to be all in parallel, and use it from a lower voltage source.

geoffwnz

1587 posts

Uber Geek

ID Verified

#1348377 21-Jul-2015 14:35

I have much the same issue.
I deliberately turn off the full bottle and only ever have one bottle on at a time as I found that it wouldn't completely empty the in use bottle before switching over and it then seemed to backfill the "empty" bottle to a degree. And yep, the "detection" method for an empty bottle is the unexpectedly cold shower.
It may actually have been that it ran out at night when it was really cold, then warmed up a bit the next day and provided more usable gas again.
I do notice that I can go through a bottle in as little as two weeks in winter vs up to 8 weeks in summer. I only have 1 gas flame effect heater and Infinity on demand hot water. So part of that difference is using the heater in winter. But I'm guessing part of it being the temperature difference of the bottles. Upper Hutt can get to or below 0 reasonably often during the night in winter.

Genesis Energy specifically notes that a bottle replacement is a full bottle no matter how much is used from it. Costs the same and no credit for partially used bottles.

MotorDrive Rallying

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