Triangle Tube Prestige 155 ACVMAX / 60 gallon indirect DHW install

cpb282

Greetings, I'm about 30 miles north or NYC and just had a Triangle Tube Prestige 155 ACVMAX installed with a 60 gallon Smart indirect DHW this past week. We have baseboard convectors, 3 zones. I'm curious as to what you all think of the installation (the good, the bad, and the ugly). See the link to the video below.
It replaced a 1960s steel boiler (AGA output 140k btu/hr, net output 123k btu/hr).

https://youtu.be/QYgKGnuLNIA

Thanks,
CPB

Robert O'Brien

I think it's way over sized!

cpb282

I was a bit concerned about that. Their initial gut reaction was a 175. I said I thought that was large. They said they did a heat loss calc and said that I was right, and suggested a 155. I don't have results of the heat calc. It may end up working out as we're considering an addition down the road (not that the installer knew that).

Paul S_3

sq ft of home?

cpb282

2,500 SF colonial built in the mid 1960s.

cpb282

By the way, Paul. I was born and raised in SI, on the north shore.

Paul48

Wayyyy Over-sized

cpb282

I did have another contractor do a heat loss calc and he suggested 110, which is why I reacted to the 175 as being oversized. I appreciate the opinions - this is a learning experience for me.

cpb282

I guess not much I can do about it now other than make it be a learning experience for others. I feel better that I pushed back on the 175 and that it is a modulating boiler (I considered an atmospheric).

Ironman

The workmanship looks fairly neat, but as others pointed out, the boiler is twice the size you need. This will result in shorten boiler life and less efficiency.

I would recommend that you download SlanFin's heat loss app and do your own calc. Then make the contractor produce his. I seriously doubt that they did a proper one based on ACCA manual J. Then tell them they can either remove the present boiler and install the correct size or add a properly sized buffer tank at their own expense.

cpb282

I appreciate the suggestions. Will the fact that it is a modulating boiler reduce short-cycling?

cpb282

Thanks. I'll see what they say and will report back.

Bob Bona_4

Obscenely too big, Chris. Your heat loss was 69,985.

Bob Bona_4

He's at 2400 Sq ft. One room was a garage, likely on sleepers from the elevations. 11, 153 loss there. Another notable was a dual fireplace in the kitchen and the living room on opposite side (15,000 kit, 12, 612 lr). Rest of the house was typical.

Bob Bona_4

I'm plugging in slab on grade, with 2 outside walls, no edge insulation. 2 full outside walls, and a partial third. 400 Sq ft area. Ventilated attic with R 19 above. Kitchen has a long exposed wall with 2 windows and a slider. Living room has 3 exposed walls, 2 which have windows. Kit and Lr are over unheated basement.

Loads are fun bc you catch areas that at first seem not that consequental, bear a closer look.

Paul48

That's a shame, because there is equipment available at his heat loss that is really well matched with better range. It never ends!

smithfan

Hatterasguy said:

Unfortunately not.

The boiler reduces its supply water temperature as the outdoor temperature climbs. This has the effect of making the emitters (the baseboards) smaller. They put out less BTU's with lower water temperatures.

The boiler also modulates itself as necessary to feed the baseboards. However, the problem occurs when one zone calls and needs, say 8,000 BTUH. The boiler has a minimum output of 25,000 BTUH. So, it quickly reaches its temperature setpoint and shuts down.

The 80 has a minimum firing rate of 14,400 and it, too, will be too large for a single zone in warmer weather. However, it's far more manageable than 25,000.

The best thing you could do with that boiler, short of getting it replaced, is to eliminate the zoning. When one zone calls, all zones get flow. You balance the house with a set of valves to keep the temperatures in all zones approximately equal.

^^ This is essentially what I do with my 110 on a house half the size, about 1400sf, my zones are not combined, so I try and run them succinctly as much as possible. The idea is to get as much water volume running through your system as possible to avoid short cycling. If you got the time and expertise just combine the zones into one if not, run them together as much as possible. It's a constant battle with over-sized units!!