Replacing and shifting hot water cylinder - mains or low pressure?

[Rhino]

Gas installed

I had the gas installed today. I bought a Bosch Highflow 25e on special from M10M for $998 (and even got a free electric screwdriver). I also bought the Bosch control panel for $199 from Plumbing World and have set it to 50deg. The gasfitter charged about a grand for his work, and the electrician was about $50 (mates rates). Here are my findings so far.

The bad:
- It takes a long time for hot water to start flowing once the tap is turned on (about twice as long as it used to from the cylinder?)
- It's an eyesore! And it's on the front of the house, not good for street appeal.
- The bathroom taps (which were borderline to start with) now leak or trickle constantly and will need to be replaced.
- The pressure starts strong and drops in the first 30sec, until the tap is turned on further.
- When first turned on the kitchen tap makes a "thunk!" sound and splurts - hopefully this might change with new taps?
- I had to move my extractor fan vent so that it wasn't above the gas unit, and had to patch holes. I'll also have to patch holes in the kitchen wall that the gasfitter had to make.

The good:
- The HWC is gone from the kitchen!
- It was cheaper than replacing the HWC with another HWC.
- It's mains pressure.
- We'll be able to cook with gas.
- The HWC is gone from the kitchen!

I'm sure I heard the term "instant hot water" bundled in with gas several times when I was looking into it, which I've now discovered isn't accurate. In hindsight it's obvious that a tank full of hot water waiting for you to turn on a tap is instant hot water, and cold water that begins the heating process once it's coming out of your hot tap is not.

It's going to be hard to tell whether the ongoing cost is more or less than electric, as it might take a couple of months to get through a gas bottle. And we're heading into warmer weather. And the power company will most likely change what they charge for my electricity as I no longer have a HWC for them to control.

I think it will work out as a good move to have made, once we get new taps throughout. I'll need to put a bit of work in building a cover for all the pipes hanging out the bottom of the outdoor unit, pouring a proper concrete pad for the gas bottles, and making an attractive trellis surround for the bottles. I'll get used to having to wait a while for the water to heat up once a tap is turned on.

[muppet]

I understand that HWC should be set higher than 50deg but lower than 64deg for health reasons.

[Rhino]

Interesting. The control panel goes up in 1 degree increments until you reach 50, with one more push taking it to 55 degrees which is as high as it will go. 50 is just bearable without mixing in cold.

This morning I had to wait for what felt like 3 - 4 minutes before the shower was warm enough to use (and my wife had already had a shower this morning). Tomorrow I'll time it and then see if Bosch have any guidelines on how long you should have to wait.

[rockran]

why did the unit have to be at the front of the house ?

[Rhino]

The bathroom, kitchen and laundry are all on the front of the house. The gas unit was installed right where the HWC cylinder was, but on the outside of the wall (the HWC was obviously on the interior).

[rockran]

would piping to the side wall have looked worse ?

[Rhino]

I expect piping to the side wall would look the same.... but would be around the side.

I timed the hot water in the shower this morning, it took just over 3 minutes until the water was warm enough to step into. With the current shower-over-bath I can't have it right on full pressure or water goes everywhere... I expect once we've put a shower cubicle in I'll be able to open the tap right up and the hot water should come through quicker. It feels like a long to wait at the moment, but maybe that's just normal with gas?

[Psilan]

Thanks for this thread. This is exactly our situation.
Nothing is different. Almost spooky

We'll be getting a new kitchen and bathroom soon. Boarding up a door and removing the HWC gives us a lot of extra space in the kitchen.

[Rhino]

Hi Psilan, keep me posted with your progress.

If you do choose to go with gas, make sure your gasfitter takes the outlet pipe to your taps via the most direct route. It appears the outlet pipe from my gas unit (which is sitting high on the wall), goes right down to the foundation and in through a vent, then presumably back up the wall and to the kitchen tap. If it went straight in through a weatherboard it would probably be about half the length, resulting in less of a wait for the water to be hot. But then again I'm not a gasfitter!

[Rhino]

Legally, how long does a gasfitter have after completing the job before he has to provide the certificate?

[MikeO]

- It takes a long time for hot water to start flowing once the tap is turned on (about twice as long as it used to from the cylinder?)
- The pressure starts strong and drops in the first 30sec, until the tap is turned on further.
- When first turned on the kitchen tap makes a "thunk!" sound and splurts - hopefully this might change with new taps?

I think the 'thunk' is called a water hammer. I'm no plumber but Ive got it in my head that this is more likely when you have really long pipes (which you can end up with due to the 'evolution' of the plumbing over time). Is it possible that the thunk, the drop in pressure and the delay in getting the hot water to the tap are all caused by this?

[Rhino]

Hi Mike,

I should probably give you an update. The "thunk" disappeared after a couple of days, and the kitchen tap no longer spurts. It must have been to do with air being trapped somewhere?

It still takes longer than I'm used to for the water to start flowing hot, but I'll get used to it. We put up an extra curtain in the shower so we can turn it on a bit harder to get the water flowing a bit quicker... once I put the new shower cubicle in (and new tapware) i'm sure everything will be fine.

The pressure still seems to drop off in the shower, to the point where if you don't notice in time the flow seems to be too little to keep the burner going, and suddenly it's cold. It's really frustrating and is worst within the first 30 sec of being turned on. Again, I'm sure this is more to do with the old tapware, so after the bathroom reno everything should be good.

I'm resisting the urge to tell you about the particular gasfitter I used... but if anyone needs a recommendation for who NOT to use feel free to PM me.

[pl]

When installing gas, do you not need a plumber involved at all? And has anyone used those water pumps (on trade me) to increase pressure on low pressure systems?

[MikeO]

When installing gas, do you not need a plumber involved at all? And has anyone used those water pumps (on trade me) to increase pressure on low pressure systems?

Yip you do need a plumber but I think a lot/most gas fitters are plumbers as well. Haven't used the water pumps sorry.

[Rhino]

Hi Psilan,

I was just reminded that you are about to undertake a gas installation. My saga is still continuing - I'll update this thread once it's resolved - but whatever you do, please go to this link and search for the gasfitter you plan to use:

https://www2.pgdb.co.nz/PGDB/PublicRegister.aspx

You need to ensure that they hold a current license for gasfitting and plumbing. If they're a craftsman that's even better. If they are listed as having no license, or aren't listed, use someone else.

http://www.pgdb.co.nz/