Started as needing one new AC setup, now maybe boiler too

SBradley

We purchased this Massachusetts house 2 years ago, built in 2004. Gas Heating, 3 zone a/c & heat.
The previous owners never had the boiler serviced.
* It is Burnham RV6N, BTU (Input)164000 and (output)143000. installed early 2005.
* House is a bit over 3200sqft - 3 full bathrooms and one half bath. (& 2 teenagers)
*Water tank was replaced in 2013, its AO Smith 50 gal.
- we have had a few proposals, some say we should replace the water heater, all three AC systems and replace the boiler.

My questions on the boiler are:
1) The gas pipe leading to the boiler is very corroded and quite rusted at the joints, as are the (I hope this is the right word) check valves and circulators on the pipes leading to the individual zones. should we have those fixed, or just replace the whole boiler?
The system we were quoted on is the Lochinvar KHN155. and a new water heater is also noted in the quote. I do not think that we need a new water tank, as this one is from 2013.
what would you all suggest?

Not sure if this is the right place for this portion of my post, but thought it would be best in one section.

we have 3 ac zones, with (qty 2) Three ton condensers and 1 two ton condenser.
The US AC Products Evaporator Coil on one unit is completely disintegrated. With R22 we need a new condenser and coil.

HVAC people have quoted us with systems that allow for the MassSave rebates on the AC replacements ($750 each up to two) - not sure if it is worth it to 1) replace all three systems as only one is in need of replacement 2) maybe a discount for purchasing 3 at once makes it a good idea?
3) Some people have told us that the current 3 ton, 3 ton and 2 ton are too big for the house, and could go down to a 2.5 Bryant 116BNA030, with the Bryant FV4CNB002L air handler.
Others have said that we need the 3 tons, and yet another suggests we go with a Carrier system utilizing a variable speed air handler.

We are planning to be in this house for around ten-12 years- and were just going to start planning a kitchen remodel, so.. timing is not great. We do not need to use the MassSave Loan program, but the zero interest is nice. However over all savings is kind of where we are at.

Any advice is very much appreciated!

JUGHNE

This sounds like a very good candidate house for a heat loss and heat gain study. 2004 is a pretty new house. 8 tons is a lot of cooling, (meaning cold and clammy house) how is your humidity in that area?

Just to put that in perspective, we have a movie theater with AC designed for 100 well fed people, sitting side by side, sweating here in 95 degree humid Nebraska. It is even over cooled by the 8 tons installed on 3 zones.

Even by the "rule of thumb"...."shoot from the hip"......quick and dirty calculations....(which usually oversize everything---contractor never comes up short), you have twice of what you probably need for MA.
IMO

(Except maybe for the teenage showers, but rationing is a good training tool for the future )

SBradley

JUGHNE said:

2004 is a pretty new house. 8 tons is a lot of cooling, (meaning cold and clammy house) how is your humidity in that area?

Even by the "rule of thumb"...."shoot from the hip"......quick and dirty calculations....(which usually oversize everything---contractor never comes up short), you have twice of what you probably need for MA.
IMO

(Except maybe for the teenage showers, but rationing is a good training tool for the future )

So, we are kind of humid in the summers, not like tropical areas, but summer is pretty humid. In this house, we have very low humidity with the current system. We keep the heat around 66, and people are cozy, where other homes are cozy at 70. (like our old house)
The AC cranks... like you get freezing sometimes if the thermostat is changed by the hot sweaty kids!
in one room, it is a vaulted ceiling family room 25'x25', that has the 2 ton all to itself. There are three steps up to this room from the main floor.
So basically you are saying that we could go with smaller systems and be just fine?
As for the boiler, would you suggest replacing the whole thing, or just replacing the circulators, check valves, etc?
(& is it normal that they want to charge us almost 300 to come and check out the boiler?)

JUGHNE

You need a room by room heat loss and gain.
You can do this yourself, there are on line programs you can use.

Having the 3 zones is to your advantage as there is overlap in the cooling.

Pictures of your boiler and piping gets a lot of attention here.
Back up to get the piping, controls and pumps.
From all 4 sides.

Henry

Rusty on the outside pipes and fittings are signs of high humidity and do NOT need replacing. A 2004 house should not need the heart of the HVAC replace. You need a pro to analyse the cause of your problems and not a part changer.

JUGHNE

A 2004 house with AC should have some supply vents into the basement which should have kept the humidity down.

High humidity is indicative of over sized AC.
The only way an AC lowers the humidity is by running longer.
Large units will short cycle on temp and not necessarily remove humidity. People overcome this short coming by lowering the temp even more to feel "comfortable".
Smaller units naturally have longer run times and more de-humidification will take place. You will be more comfortable with low humidity and even higher temp. (think Phoenix or Vegas)

What cooling temp do you run the house at?
You said 66 for the heating?

How is the evap coil "disintegrated"? and which unit is it on?

There are many factors in sizing AC, mainly sun exposures for windows. East and West naturally give the most heat gain.

EBEBRATT-Ed

Both the boiler and the AC seem to be too large. You need someone who can do a complete, accurate heat loss and heat gain calculation. That's the first step.

I would not replace a functioning ac system until it fails. Only replace the one you need to replace.

Get prices on an indirect water tank and compare that to the gas hot water replacement.

Boiler seems quite large.

Rusty pipes need wire brushing and painting. As long as there not leaking their fine.

If the boiler isn't leaking and the combustion efficiency and safety is ok why replace it?

Yes, most of this equipment is pushing 13 years old.

I would start budgeting for replacements

No need to do it all at once

steve2017

You can do this yourself, there are on line programs you can use.
Having the 3 zones is to your advantage as there is overlap in the cooling.