Combi choice

Bob_115

I'm converting from oil to gas and need to decide which combi boiler to choose. The Burnham Alta and the Laars are under consideration. I was told that the Alta would need wide open taps to supply hot water as my supply line are 1/2 inch copper. The Laars has a small internal tank that would make this unnecessary. Any thoughts comments or advice would be appreciated.

hot_rod

Typically a combi starts the DHW mode based on water flow, .35 or .5 gpm flow. In some with low flow lav faucets you may need to flow the hot wide open to trigger the boiler.

Those are both good brands, Lochinvar is another.

You can run a combi "always hot" which reduces the boiler start lag. Or on demand which takes time for the boiler to rev up.

A small tank inside eliminates the lag, but maybe uses a bit more fuel to maintain the tank temperature.

Jamie Hall

Whatever — size it properly. The trick with a combi s in getting enough power for your hot water needs — 199,000 BTUh is none too much for a normal house, never mind a rain shower or somesuch — and at the same time enough turndown soo it can manage your heating load, which is usually a lot less.

Bob_115

I've seen some comments about parts for the Laars are not readily available ,Has that been your experience?

I have 1 bathroom and i use a low flow shower head. We have learned to only use one fixture at a time.

hot_rod

for your dhw use a combi should provide plenty of water

A 120,000 would supply 2-2.5 gpm , depending on incoming water temperature. That is plenty for most showers, 1.5 gpm

If you want a bit more a 150,000 is an option.

I gad a Laars combi years ago, it was a Baxi I believe, it was 16 years old when I replaced it to sell the home