Number 1 Reason Pipe Sizes Matter. You Need to See

Why do you need to know your pipe sizes before deciding on a hot water system?

Have you ever heard a saying ‘you get what you pay for’? Well, this is a classic example of that. In the video below, we’ll show you what happened and explain why it’s so important to know your pipe sizes.

The Present Issue

We had a job at a rental property with a new hot water system installed about a year and a half ago. The owners called us directly because they’ve just had a gutfull of this thing working intermittently. He said, “Can you come out and just have a look? I’m just tired of it. I just want it sorted. I’m sick of the phone calls.” The lady just had a baby so she just wants it to work. That’s all she wants. It’s not that hard.

The Past Issue

Obviously the real estate said, “Okay, we need a new hot water system in.” And so they probably got three quotes from three different plumbers. And the plumber who won the job decided that, probably the cheapest one, to put the Rheem Pronto 12 in.

Now normally there was a storage hot water system here. And you can tell that by the slab where the hot water system used to be. The storage hot water systems usually have about 40 megajoules, while the Rheem Pronto has about 100 megajoules – well, 99, to be exact. So it’s a fair bit more gas – more than double.

And yet, it has a 15 mil pipe going into it. The cold – the feeder – and the hot outlet are both 15 mil, and then they’ve got the 20 mil gas main that goes straight off into the small pipe. So really, that should have been enlarged. The 20 mil pipe should go all the way back to the meter.

But the thing is, the meter is on the far side of the house. So the gas pipe must go up all the way across the house – over the garage. Then on the gas meter there is the 20 mil gas pipe. Now we go up in the roof to see how they hooked up the pipes. We’re hoping they haven’t hooked the 20 mil onto the small 15 mil pipe. Because, you can imagine, if the whole house is on that small pipe for the hot plate and the bayonets and everything, anytime you turn any of that on, it just starves the gas.

The Pipe Size Issue

We’ve found the gas pipe on the roof as you can see in the video. They have about three meters of the 20 mil pipe and then it runs into the smaller 15 mil pipe. And then there’s the first tee – one of them would be for the hot plate and the other goes off to the bayonet for the barbecue or the room heater. And then there is a pipe that goes all the way across to the other side of the house where the hot water system is.

That’s why the hot water system doesn’t work, because the gas pipe is so undersized. It’s real disappointing for the owner. That’s why it’s very important to get the pipe sizes right.

Some plumbers are a lot cheaper, but that’s because they’re not playing by the rules. We’ve got all these rules, the gas standards and the Australian standards that we’ve got to stick to, like the pipe sizes, etc.

The Options

So now they’ve got two options. We can either just enlarge this gas block 20 or so meters all the way to the other side to get that little hot water system up and working where it is. Or we could move it near the kitchen sink which is in a way better location. There’d be less gas pipe because we only have to go a little bit of the way across from the gas meter.

The Decision

So we rang the owner to tell them about the situation and their options. They’ve got a Rinnai B16 at their place that we installed about three years ago and they’ve been stoked with that one. So they just want the same one on this rental property too. They don’t want any more dramas for the tenant.

So we are going to shift the hot water system to a better location. The kitchen happens to be near the meter box so it’s not going to be hard to connect all the pipes up. So we can put the hot water system on the wall next to the kitchen.

Now the reason it needs to be near the kitchen sink is if you’ve got new baby and you just want a washcloth to wipe their face, as you’re waiting for that water to come through, from the hot water on the other side of the house like it is now, all that wasted water would come through of cold water before you get the hot. And then once you finally got a little bit of hot, you’re finished and you turn it off.

But if you have the hot water system next to the kitchen, you’re going to have hot water within five seconds and you can wash your plates and heat up the washcloth for your face or for your kids. And then you can turn the water off.

You’ll waste a bit of water going over to the shower and the bath, but with the shower, the water is on for a minimum five minutes. So by the time you get your clothes off, the water is going to be hot and you can start using it. Meanwhile, for the kitchen sink, it’s on and off all the time. So that’s where you’ll save a fair bit of money and water by not wasting it.

The Result

We found the 20 mil main up in the roof above the garage. We cut a nice tee and ran a nice 20 mil main all the way down. Then the hot water system is up on the wall next to the kitchen with the 20 mil gas main goes into it. The 15 mil feed goes up in the roof, tapped it into the 20 mil main and comes down to the kitchen sink. The hot main also goes down and straight in to a tee under the kitchen sink, and from there, it goes up to the rest of the house.

They’re noticing that right away that within five seconds they’ve got hot water. They’re loving it. The flow is a lot better. It’ll be hotter as well. So they’re pretty stoked, which is great

So, the moral of the story is, most of the time you do get what you pay for. I know there’s guys out there who are happy with the cheapest thing. They get the best deal, best rate, and that’s cool. But, at the end of the day, it’s always going to bite you in the bottom (just in case kids are watching this video).

There are many different models out there. Some are really economical, some aren’t so much. All also depens on your pipe sizes.

If you need some advice on that, please give us a call. We’re happy to come out and look at your situation and give you some options.