Please advise on this boiler/water heater quote.

[J.P.JONES]

This is from a plumber who does a lot of business in our town. There are seven zones on the current system.
Does it seem reasonable to you? We are in Rhode Island. Many thanks!!!

 

[John Gayewski]

Could be. Do you currently have a system? Why the complete repipe?

 

[Sponsor]

 

[Tuttles Revenge]

Does which part of the estimate seem reasonable? Its not only impossible for anyone outside of that market to compare prices, but also I wouldn't offer an opinion on the price unless I was there to give a competitive bid. Which you should get if you believe that the price is unreasonable. And we don't even know the scope of work, square footage, current condition of the work space etc.

 

[J.P.JONES]

There is a current baseboard system in place. I know it's impossible to offer the sound opinion, without knowing the specifics. I looked , and the equipment cost is about $8000-$9000, the rest of it is all his labor charges, $10,000. He says it's a two-day job. The extant boiler and hot water tank are 1990s, and inefficient, rated at about 70%. It's located in the middle of the basement. He said he will repipe, and hang the new boiler on the wall.

 

[Dana]

There is a current baseboard system in place. I know it's impossible to offer the sound opinion, without knowing the specifics. I looked , and the equipment cost is about $8000-$9000, the rest of it is all his labor charges, $10,000. He says it's a two-day job. The extant boiler and hot water tank are 1990s, and inefficient, rated at about 70%. It's located in the middle of the basement. He said he will repipe, and hang the new boiler on the wall.

Are you sure the Viessman is even appropriately sized for the loads ? In particular the individual zone loads, but the whole house load may be too small too.

Use the existing boiler and last winter's fuel use as a measuring instrument to find out the whole house load, using this methodology.

Then, zone-by-zone measure up the baseboard, and see how much modulation or condensation you'd be able to get out of that boiler, using these methods.

The B2HB-160 has a minimum modulation input of 32,000 BTU/hr, which is enough to keep my not-super-insulated sub-code 2400' antique 1920s bungalow home (a bit north of you in Worcester, MA) at 70F indoors down to somewhere around +15F - +20F outdoors. And that's at it's MINIMUM firing rate! Even though that series is designed to operate reasonably efficiently in "pulse mode", with very short, bursty burn cycles, it's likely to never operate in anything BUT pulse mode if significantly oversized. Running literally dozens of ignition cycles per hour isn't really great for any equipment.

Without a buffer tank (or a thermally massive version of a low loss header) with seven zones you are likely to experience efficiency-robbing (and lifespan reducing) short cycling on zone calls when the minimum firing rate that high, even when operating at temps above the condensing zone.

 

[Fitter30]

How did they size the boiler? Input or output should be on the output. Take a pic of the old boiler tag and noiler piping. Boiler cycle when it was 0* ?

 

[Sylvan]

Sounds very fair but ask how long he / she will give a service FREE contract

 

[WorthFlorida]

Price wise is extremely hard to comment on. Just too many variables. The bid reads removal of the old equipment. Have you brought anything to the dump lately? That can get expensive. You cannot go by the price of the equipment alone. There is big expenses behind the man working at the home and it maybe two or three man job over the course of time, and it is not all labor. What expenses you do not see is workers comp cost, insurances, other people at the shop supporting phone calls, purchasing equipment, delivery equipment to the job site, paying the rent, gas and electric bills, etc. It all adds up. The most import part is this company has been around for a long time to support any warranty and service work you may need. Equipment warranty is usually through authorized dealers and distributers only.

I attached a picture of my brothers VT home hydronic 5 zone system. Behind it all is a Boderus propane boiler. Since a few zones are floor radiant heating, there are cold water mixing valves to keep the floor temperature lower than for the baseboards. Your new installation will look something similar. These are Taco circulators with a Taco 5 zone controller. The price quote for RI seems quite reasonable.

 

[J.P.JONES]

Thank you all for the constructive points! I'll take a photo of the current system.
The plumber looked at the BTU/hr of the current system, and said that whoever installed it 25 years ago, went way overboard,and the boiler is too big for the application. House is built in the late 1920s, brick-clad, 3,900 sf., three floors; insulation is, shall we say, seasoned.

 

[Dana]

Thank you all for the constructive points! I'll take a photo of the current system.
The plumber looked at the BTU/hr of the current system, and said that whoever installed it 25 years ago, went way overboard,and the boiler is too big for the application. House is built in the late 1920s, brick-clad, 3,900 sf., three floors; insulation is, shall we say, seasoned.

Brick clad, but are the walls insulated?

Single pane windows/storms, or low-E replacements?

Are the basement foundation walls insulated?

Attic insulation?

A typical 3900' uninsulated 3 story with storms over single panes leaks air like a tennis racquet, and with the height of 3 floors (+ basement) the stack effect could raise the heat load to something like 90-120KBTU/hr @ +10F (a typical RI outside design temp- yes I know it gets colder than that sometimes.)

The same house with dense packed cellulose in the walls, a couple inches of closed cell foam on the foundation walls, and R30 in the attic could easily come in at 50-60,000 BTU/hr.

Doing the fuel use based load calculation is important for narrowing the range down.

Individual zone loads are much smaller, of course, and the zone radiation on any given zone would ideally be able to emit a large fraction of the minimum firing rate of the low-mass boiler.

 

[J.P.JONES]

There is insulation in walls, but not not up to modern standards.
Attic is also under-insulated.
Windows are double-pane Pella, 20-25 years old.
Basement foundation walls are not insulated.

 

[J.P.JONES]

299,000 BTU/HR

 

[Dana]

There is insulation in walls, but not not up to modern standards.
Attic is also under-insulated.
Windows are double-pane Pella, 20-25 years old.
Basement foundation walls are not insulated.

The priority for building upgrades would then be:

1: air seal the attic floor/upper floor ceiling plane
1a: air seal the basement walls, starting with the foundation sill & band joists.

2: insulate the attic floor (no AC or heating ducts up there, right?)

3: insulate the foundation walls to a minimum of R15 continuous insulation (current IRC code for your location) from the basement slab all the way up to the first floor subfloor above. Using 2-3" of closed cell spray polyurethane (expensive, but effective) the air sealing & insulation can be done in one step. Using reclaimed roofing foam can be a much more economical DIY approach. (Search this forum or check back for details on how to do the latter.)

4: dense pack cellulose over the existing wall insulation, which will further tighten air leakage while fully filling all voids in the insulation.

With the existing house, assuming moderate but not excessive air leakage you're probably looking at a design heat load of ~75-80,000 BTU/hr, which could (and should) be verified by fuel-use load calculation methods. Simply air sealing the attic floor & basement walls (primarily foundation sill & band joist, as well as any obvious air leaks) can knock 5000 BTU/hr or more off the load numbers without spending a lot of money.

Assuming a 75,000 BTU/hr load, using ASHRAE's recommended 1.4x oversize factor the boiler need not have an output higher than 75K x 1.5= 105,000 BTU/hr. There are mod-cons out there in that size range that have 10:1 turn-down ratios, with a minimum firing rate in the ~10-12,000 BTU/hr range, which would be much less short-cycle prone than the 32K-minimum firing rate of the B2HB-160. If you're planning to do the building envelope upgrades you can go even smaller. Most homes that size can be handled by an ~80KBTU/hr mod con with a 10:1 turn down, and it would be more comfortable too, with longer, more consistent heating cycles on every zone.

 

[J.P.JONES]

Thank you very much, again.
Here's the response from the plumber, when I asked him how he sized the new boiler:
I sized your boiler based on the rough square footage and number of zones as well as a rough heat loss calculation.

I warranty everything installed for 2 years..parts and labor
Viessman is 20 years on heat exchanger i believe and 5 on some parts.

The reason why I’m committed to these Viessman units is they are extremely troublefree
Run super clean with constant combustion analysis with self correcting adjustments.

The sizing doesn’t matter as critically..

Here’s why..

This is a modulating boiler..based on an outdoor control.
We want the boiler big enough to satisfy the heat load for all zones on a really cold day.
But what if its 50 out and only one zone is calling?
Your current boiler fires at 300,000 BTU no matter what.
EXTREMELY inefficient.
A new Viessman can modulate between 60,000 and 199000
If its 50 and only one zone calling..its a very small boiler
If its 10 and 6 zones calling..it a big boiler.
Its adjusts to the load and temperature outside constantly.
Plus..those stupid zone valves…lol
We will pipe in all zones on high efficiency electro-magnetic circulators.
Plus install a lifetime warranty Indirect water heater.