Two quotes for combi boilers for radiant and DHW

ThinkpadUser7

I'm in a 1947 house built on a slab with the original Hotstream 192-L and copper pipe radiant heating system. I'm attaching a photo for reference. The water heater behind the boiler is 40 gallons. The house is ~1340 square feet and has 3 bedrooms and 2 full bathrooms. This is in the S.F. Bay Area.




I've been looking into replacing the equipment in that closet and have gotten bids from two reputable places. Any thoughts or advice on what place to pick? The place that uses IBC does very clean / labeled work that's mounted on added wood panels. I like the aesthetics more but I'm not sure that should factor into my decision. I'm not sure why the two bids use different size boilers. The two bids are similar in price.

BID 1 (IBC SFC 199)
• 199,000 – 28,000 BTU boiler with electronic spark ignition
• Primary/Secondary plumbing module for space heating
• Descaler cartridge system for domestic inlet into unit
• Caleffi tempering valve domestic
• Caleffi 12 PSI pressure reducing valve with antisiphon backflow preventer
• Watts 30 psi presure relief valve
• Proflow 2.2 gallon hydronic air expansion tank
• Stainless steel expansion tank for domestic
• Weiss pressure/temperature gauge
• Weiss 30 psi gauge for system pressure monitoring
• low pressure cut off switches
• high and low temperature controls
• Venturi combination gas valves/electronic ignition
• B&G Air elimination system
• automatic air vents
• Grundfos Up26-99FC circulating pump
• High pressure valving for purging/testing/service on
all supply and returns – and needed safety and support equipment
• We will install the boilers in the existing mechanical space provided
• We will install a new digital thermostat
• All boiler plumbing will be in copper with wrought copper fittings and 955 leadfree soldered
joints. (Pipe, parts, fittings, unions, electrical, ties
hose bibs, caps, miscellaneous)
• All boiler piping will be insulated with a 1”/3/4” wall thermocel or equal
• All valves will be labeled according to their function

Parts Breakdown:
IBC SFC 199 Combination Boiler w/ taxes,ship
Grundfos UP26-99FC
Primary/secondary header
Caleffi Reducing valve/Backflow preventer
Proflow 2.2 stainless air expansion tank
Small Stainless expansion tank for domestic
High pressure ball valving
Hose Bibbs
Pressure Gauge
Copper pipe plus fittings
Pvc pipe for flue and condensate
Full flow gas flex lines
Galvanized pipe plus fittings for gas line
Electrical with zone relay module
Wood boards and trim
Descaler for domestic input
Bonding ground clamps
Nest Thermostat 24V or 120V high voltage digital
Piping insulation
Uni-strut, Hardware, Labelling plus miscellaneous
Total materials:
Labor to install and preparation crew @15hrs. a piece
Travel

BID 2 (VIESMANN B1KE-120)
VIESMANN B1KE-120 COMBINATION BOILER FOR SPACE HEATING AND DHW
-Demo, haul away and dispose hot stream 192-L Boiler, and Rheem 40 gallon water heater.
-Provide and Install Viessmann Vitodens B1KE-120 120,000 BTU 95% Efficient Natural Gas.
-Provide wall mounting bracket and hardware to property secure boiler.
-Intall New primary loop with integrated ECM motor circulating pump.
-Provide and install New expansion tank and water auto-fill valve for closed loop system.
-Provide and install New air separator/air eliminator trim kit.
-Retrofit with type L copper to exiting supply and return radiant heating connection points.
-Provide and install New Poly Flue intake and exhaust through existing roof jack and seal any gaps.
-Provide New gas flex, shut off valve and retrofit gas as needed.
-Provide Electrical modifications as needed to provide 120v.
-Install Condensate Drain with condensate neutralizer to floor drain/side yard.
-Provide and install New DHW mixing valve to hot and cold connection points.
-Preform a combustion analysis measurement of gas concentrations, emission checks and safety.
-Provide and install New Honeywell T6 thermostat for radiant heating.
-Remove existing galvanized manifolds/ Rebuild manifolds with copper and new brass valves.
-Fill and purge, start up and commissioning to factory specifications.

kcopp

I like and use IBC products all the time.
Im not sure why they have the 199 instead of the 125. Do you have Alot hot water demand?

ThinkpadUser7

kcopp said:

I like and use IBC products all the time.
Im not sure why they have the 199 instead of the 125. Do you have Alot hot water demand?

I don't believe so. Any disadvantage to it in this case?

hot_rod

I think your in coming water is fairly warm, so a 120 combi would be my choice. The lower the turn down the better it matches your small load.

Also keep a plan B in mind, once that copper tube starts to leak you will need to look into panel rads or a overlayed radiant system. Certainly leak test it before you get too deep into the replacement boiler.

Alan (California Radiant) Forbes

The max. DHW flow rate for the IBC SFC 125 is 4 gpm and 7 gpm for the 199 model, so that might be why they chose the larger model, i.e. more DHW. But the SFC 160 model also provides 7 gpm and that's the one I would have chosen.

I like IBC, but only the ones with a fire tube heat exchanger - model CX combi. The SFC's have a Labryinth heat exchanger, not my fav. Parts are stocked at a supplier in Richmond; always a good selling point.

I've installed 3 of the V. B1KE's and service a few others that we did not install. I like the 26.5 gal. storage tank and they have been very stable workhorses. The only thing with V. is that parts are not available locallly. East Coast at best.

Call me if you have more questions (510)773-9870. I'm in Berkeley.

Correction: I've confused the B1KE with the 222-F. The B1KE does not have the storage tank that the 222-F does.

ThinkpadUser7

hot_rod said:

I think your in coming water is fairly warm, so a 120 combi would be my choice. The lower the turn down the better it matches your small load.

Also keep a plan B in mind, once that copper tube starts to leak you will need to look into panel rads or a overlayed radiant system. Certainly leak test it before you get too deep into the replacement boiler.

I should ask them to do a leak test as a first step of the installation? I assume it's kind of a point of no return once the equipment is disconnected for a leak test. If there are difficult to fix leaks then continuing to use the radiant system might not make sense, and I suppose a pressure test could end up causing issues.The IBC place also specializes in leak repair and said they do a pressure test to ensure they can warranty it, but I'm not sure if they were planning on that doing before or after the install.

The other option is to completely abandon the radiant heating and do something like a mini split system (~67% more expensive) but I would prefer radiant heating. I do have an attic but it sounds like mini splits are easier.

bburd

If the floor coils are leaking you could use panel radiators or hot water baseboards. Make them large enough and a condensing boiler could run in its most efficient range most of the time.

hot_rod

Is some AC capacity is desirable? If so a mini split or ducted system is a better choice.

Or panel rads and mini splits just for cooling. But now you are looking at more $$

That 77 year old copper tube would make me nervous. But if it fails having an option to add panel rads or radiant ceilings or radiant walls would give you the ability to still use the combi.
I would guess any contractor would first pressure test a system that old, I would insist on that.

Here is the spec on the IBCs The DHW is based on a 70° rise. In your area it looks like 57- 60° incoming water. So with a 110 supply, plenty hot for a shower, that is a 50° temperature lift. So over 4 gpm of dhw with a 125 is reasonable.

ThinkpadUser7

AC would be nice but the house doesn't get very hot so it's not something we think about 11 months of the year.

Would the IBC SWC 199 just be overkill for my situation or would it be noticeably worse? Having extra capacity seems useful but maybe not if it runs much less efficiently.

hot_rod

Ideally there would be a heatloss calculation included with the bids you received?

A wild guess would be 26,000 BTU/hr or less in that sized home in your area.

The 125 has a low firing rate of 15,000 btu/hr. While the 199 has a 27,000 low turndown.
So even on its lowest firing rate the 199 may be oversized.

It really comes down to how much hot water you want or need. 4 gpm would run 2 showers wit 2 gpm shower heads for example. If you run the washer, dishwasher, two showers all at the same time you would not have adequate hot water.

So you need to tell us what you expect as the DHW load could be larger than the heating load. You need to size to the largest of the loads. In small heat load homes the DHW load is often the larger.

If you have had a tank style heater the difference is the dump load from a tank, then the 20- 30 minute recovery. With combi the flow is endless within the operating conditions, as an example 4 gpm now until the cows come home.

ThinkpadUser7

In the past we've avoided running more than one of these at the same time: washing machine, shower, dish washer, and we've never run two showers at the same time. But this house might become a rental at some point so maybe I need to account for somewhat more aggressive usage.

FWIW, i don't think either shower is low flow. I actually put a flow restrictor on one of them because I found the flow too forceful. We have one bathtub as well but don't use it often.

Alan (California Radiant) Forbes

I don't mean to complicate things, but Lochinvar is slowly becoming my favorite boiler because they have shown themselves to be trouble free when installed properly. They have a Noble floor mounted (or wall-mounted) combi that may be right for your mechanical space. The midsize 150 model modulates down to 15,000 BTU and provides almost 4 gpm at a 70° rise.

Pace Supply in Oakland has them.

https://www.lochinvar.com/products/residential-boilers/noble-fire-tube-combi-boiler

hot_rod

I had a 110 Nobel combi in my last home. If you do have water temperatures around 60F, you should get over 3 gpm from this. A nice low turn down also. Very easy to work on compared to some of the other combis.

It is more of an entry level model compared to their Knight. Less control functions and the Kiturami heat exchanger from Korea.

ThinkpadUser7

Alan (California Radiant) Forbes said:

I like IBC, but only the ones with a fire tube heat exchanger - model CX combi. The SFC's have a Labryinth heat exchanger, not my fav. Parts are stocked at a supplier in Richmond; always a good selling point.

...

I've heard others say that they don't like the SFC heat exchanger as well, so it does give me some pause.

Do all of these combi boilers require a yearly 1.5-2.5 hour maintenance visit (that's what the Viesmann shop quoted when I asked)? That's definitely worth consideration given the high labor rates in the area.

I'm in Palo Alto, BTW.

kcopp

ThinkpadUser7 said:

Alan (California Radiant) Forbes said:

I like IBC, but only the ones with a fire tube heat exchanger - model CX combi. The SFC's have a Labryinth heat exchanger, not my fav. Parts are stocked at a supplier in Richmond; always a good selling point.

...

I've heard others say that they don't like the SFC heat exchanger as well, so it does give me some pause.

Do all of these combi boilers require a yearly 1.5-2.5 hour maintenance visit (that's what the Viesmann shop quoted when I asked)? That's definitely worth consideration given the high labor rates in the area.

I'm in Palo Alto, BTW.

I have about 150 of this Heat exchanger version installed.
(HC, DC and now the Superflow.)
It is very simple to pull apart and clean.
Lots of happy customers.
Curious as to why some dont like the heat exchanger??

ThinkpadUser7

kcopp said:

ThinkpadUser7 said:

Alan (California Radiant) Forbes said:

I like IBC, but only the ones with a fire tube heat exchanger - model CX combi. The SFC's have a Labryinth heat exchanger, not my fav. Parts are stocked at a supplier in Richmond; always a good selling point.

...

I've heard others say that they don't like the SFC heat exchanger as well, so it does give me some pause.

Do all of these combi boilers require a yearly 1.5-2.5 hour maintenance visit (that's what the Viesmann shop quoted when I asked)? That's definitely worth consideration given the high labor rates in the area.

I'm in Palo Alto, BTW.

I have about 150 of this Heat exchanger version installed.
(HC, DC and now the Superflow.)
It is very simple to pull apart and clean.
Lots of happy customers.
Curious as to why some dont like the heat exchanger??

This mainly came from a discussion I had with the person I've used to fix my radiant heating system in the past. I think he didn't like the two-in-one design. He mentioned he had been hired to do maintenance work on these IBC units in the past and found them difficult or impossible to clean, though he did admit they were cases of neglected maintenance. So his advice if i get one was to make sure to maintain it regularly.

What are your thoughts about the needed frequency of maintenance and number of hours required?

hot_rod

My take on mod con service interval. Open it after the first year and check the combustion chamber condition. Sometimes you find a perfectly clean HX, other times a gunked up, plugged HX. It depends on what they breathe and how well they were dialed in.

If they are considerable junked up, recheck combustion and consider an intake air filter, which more brands are offering, finally!

If the system is clean after the first year I go 2 or 3 seasons and check it again.

Time to open and clean depends on location for access, type of HX, and service technicians skill or experience level with the particular model.

Plenty of homeowners are capable of doing a service clean and check. Lots of You Tube vids to take you through the process

Water quality is equally important to keep scale build up off the wet side of the HX.

Alan (California Radiant) Forbes

Alan (California Radiant) Forbes

What are your thoughts about the needed frequency of maintenance and number of hours required?

Fire tube HX require less maintenance as they are self-cleaning. Gianoni HX should be cleaned every 1-2 years, especially on high mass (radiant) systems.

Condensate pellet replacement, combustion analysis, inspect the venturi, look for leaks at sensors, etc. should also be done by a trained technician. In my area, it's hard to find anyone with a combustion analyzer let alone someone qualified to run it. Most installers want to install.

ThinkpadUser7

Alan (California Radiant) Forbes said:

What are your thoughts about the needed frequency of maintenance and number of hours required?

Fire tube HX require less maintenance as they are self-cleaning. Gianoni HX should be cleaned every 1-2 years, especially on high mass (radiant) systems.

Condensate pellet replacement, combustion analysis, inspect the venturi, look for leaks at sensors, etc. should also be done by a trained technician. In my area, it's hard to find anyone with a combustion analyzer let alone someone qualified to run it. Most installers want to install.

How is the B1KE-120 classified here? Sorry, I'm not too familiar with this terminology.

Alan (California Radiant) Forbes

How is the B1KE-120 classified here? Sorry, I'm not too familiar with this terminology.

Viessmann's Inox-Radial HX is basically a rebranded Gianoni HX. I grew up on Gianoni HX (Munchkin) and appreciate their design and will last you 15-20 years. The fire tube HX requires less maintenance (self cleaning) and - based on what I've seen - will last 20-25 years. And not necessarily because the HX fails.

As an aside: Gianoni HX are easy to access and clean; nice, because they need cleaning every now and then. Fire tube HX are difficult to access; you have to almost disassemble the boiler housing to get enough room to lift off the burner plate and gas valve. And then, when you put it back together again, you carefully torque the bolts to 44-53 in-lbs. Over tighten them and the bolts shear off and you have to replace the entire HX. So, nobody cleans fire tube HX. Nice, because they don't really need cleaning anyway.

Glad you asked?

I'd say 5% of my customers call me every year before the heating season to service their boiler. Another 5% call me every 2 years. The rest call me when something goes wrong. Do the boilers belonging to the proactive customers last longer? Of course they do.

ThinkpadUser7

Alan (California Radiant) Forbes said:

...

Glad you asked?

Yes, thank you! That helped clarify.

kcopp

On Natural gas typically every 2 years.
I can do a full proper cleaning in 1 to 1 1/2 Hours w/ a combustion test.

The one that Alan shows had something else going on.
I have never had one even close to that bad.

LP gas will typically be dirtier to clean.

@Alan(CaliforniaRadiant)Forbes What the story w/ that one? How many years between service and was the combustion off or an outside contaminate?
Is that a TT Challenger?

Alan (California Radiant) Forbes

@kcopp Natural gas; never been serviced, combustion was fine; some leaves were sucked in, but not many. And yes, TT Challenger. 

It sounds as though you’ve serviced more of these than I have and I’m being too harsh. Do you clean the HX every service call?

kcopp

Yes. So typically every other year. Its takes no time at all and folks are happy to have it done.
The other thing you need to watch out for is the gasket/O-ring that can break down over time...especially if it not serviced.

ThinkpadUser7

hot_rod said:

...
Here is the spec on the IBCs The DHW is based on a 70° rise. In your area it looks like 57- 60° incoming water. So with a 110 supply, plenty hot for a shower, that is a 50° temperature lift. So over 4 gpm of dhw with a 125 is reasonable.

FWIW, tonight is particularly cold and I just measured the incoming water at 46 degrees. Not sure if that changes your assessment.

hot_rod

ThinkpadUser7 said:

hot_rod said:

...
Here is the spec on the IBCs The DHW is based on a 70° rise. In your area it looks like 57- 60° incoming water. So with a 110 supply, plenty hot for a shower, that is a 50° temperature lift. So over 4 gpm of dhw with a 125 is reasonable.

FWIW, tonight is particularly cold and I just measured the incoming water at 46 degrees. Not sure if that changes your assessment.

It's all in the numbers. The colder the incoming water temperature the lower the GPM you can expect.

Manufacturers often include DHW performance charts or tables. There are all sorts of online tankless calculators. Or do the number crunching on a ThinkPad

But you need to input accurate information, how much DHW you want, to get an accurate answer.

It is a balance act with a combi. You don't want to grossly oversize just to get large DHW flows. At some point it makes more sense to have a separate water heater, indirect tank.

If mechanical room space is part of the determining factor, choices become more limited.

For the most part first time tankless or combi owners learn how to work within the capacity of the unit. If they are not happy, switch them back to a tank style heater. Pros and cons both ways.

I doubt a reputable contractor would install a system like you have now with no access to the HW tank for service or repair.

ThinkpadUser7

So the space heating aspect can be ignored in terms of determining sizing because the amount of flow needed is so tiny?

hot_rod

ThinkpadUser7 said:

So the space heating aspect can be ignored in terms of determining sizing because the amount of flow needed is so tiny?

Yes, you need to size to the bigger of the loads. This is true if it is a combi, or traditional boiler with an indirect HW tank.
A typical gas fired water heater will be around 35- 40,000 BTU/ hr.

We are guessing a bit at your actual heat load. That size home in that climate is all we have to ball park a heat load.

Corey works for Skaates Plumbing out of Burlingame. He is good at squeezing 50 lbs of potatoes into a 25 lb sack See below. If you are still looking for bids or options. Hundreds of pics on his IG hydro_tech510

Next time I do a dual system I would buy a standard mod con boiler, Lochinvar Knight, add a plate HX below it with a dedicated pump. That could fit in any of these pics below. A site built combi without the diverting valve and special OEM parts inside.

You still have the unknown of how many years that copper tube in slab will last. Maybe now is the time to address that in the rebuild?

ThinkpadUser7

hot_rod said:

...

Corey works for Skaates Plumbing out of Burlingame. He is good at squeezing 50 lbs of potatoes into a 25 lb sack See below. If you are still looking for bids or options. Hundreds of pics on his IG hydro_tech510

Next time I do a dual system I would buy a standard mod con boiler, Lochinvar Knight, add a plate HX below it with a dedicated pump. That could fit in any of these pics below. A site built combi without the diverting valve and special OEM parts inside.

You still have the unknown of how many years that copper tube in slab will last. Maybe now is the time to address that in the rebuild?

Is Corey on this board? I've been trying to get a bid from Skaates over the past few weeks, but I gather they're pretty busy. The installs look very clean!

I assume addressing the copper tube in the slab would be an order of magnitude more work so I'm hesitant to pursue it at this point. We'd have to move 50 years worth of furniture/stuff to storage, rip out all the carpeting and original hardwood flooring, etc

hot_rod

I think the younger generation of hydronic guys and gals hang on IG. More potential for fame, $$ and bling when you "influence"

Might try Corey directly, I think he bids and installs most of the radiant for Skaates?

His recent posts with pics of 4" seps make me think he is on a large commercial project?

As far as the copper. Pay to pressure test it before you commit. Hopefully the other bidders suggested that?

ThinkpadUser7

hot_rod said:

...
As far as the copper. Pay to pressure test it before you commit. Hopefully the other bidders suggested that?

One bid I got was from a place that also fixes leaks in the slab. They said they would do a pressure test as part of the install for the purpose of determining whether they could honor the warranty. Leaks would need to be fixed with a couple months of install. They didn't seem to think leaks were likely. This was the IBC bid above.

Most of the other places I've talked to didn't suggest doing a pressure test, even after I asked about the condition of the existing pipes. One used a heat camera, which showed the floors as mostly yellow (system had only been on for about 3-4 hours prior), and he said it seemed to be working ok. Most asked if I had seen water near the slab (I have not).

One place said they'd be reluctant to replace the equipment given the age of the system and said a pressure might accelerate failures because the pressure is much higher than typical usage.

I'm also not sure how much a "point of no return" the test would be. If they need to disconnect a bunch of that equipment and then they find a bunch of leaks, then it's not really clear what the next steps are... try to fix the leaks? Abandon the system entirely? Try to re-hook up existing system and get it working again to tide us over until we can evaluate mini split, etc? Would it even be practical to re-hook the old system temporarily? I had a gas leak 10 years ago that required the radiant boiler to come out of the closet and it took some work to get it running again.

I'm trying to find a sensible path here but (as I'm sure you can tell) I'm not super knowledgeable.

hot_rod

If there are no leaks in the system as it is currently installed, that is the best info you can get.
My thought would be if you are doing any changes or remodeling in the home, think about how a different hydronic system could be added if a leak does develop.
\Maybe some piping route options if panel radiators were to be added..
If you invest a new boiler you want to be able to use it for heating and DHW for years to come.
Perhaps the bidders could give you suggestions on any radiant systems like yours that they have retrofitted in your area.

SgtMaj

I would use a straight condensing heating boiler with an indirect water heater. Or boiler with plate Heat exchanger and insulated storage tank. I’m just not a fan of combi boilers. Which ever you choose you’re going to need more room to service it.

ThinkpadUser7

As an alternative, the place that gave me the quote on the Viesmann just gave me a quote on the NTI FTVN150C. Would that be a good choice? It appears to be a fire tube heat exchanger.

hot_rod

NTI is a good option. I think Osborne Sales is the local rep and they have good support should you ever need it.

pedmec

lochinvar noble wall hung is a fire tube heat exchanger and an excellent product as i have done a couple of dozen with no problems. still haven't received any complaints after years of installs. uses a flat plate heat exchanger for hot water. If space is an issue this is the way to go.

ThinkpadUser7

Can anyone recommend a place that services Palo Alto that installs the Lochinvar Noble? Thus far I've only come across places that do IBC, Navien, Triangle Tube, NTI, and Viesmann.

Larry Weingarten

Hi, The best person to ask is @Alan (California Radiant) Forbes . If he'd take on the job, you could know that it would be done right.👍
Yours, Larry

Le John

pedmec said:

lochinvar noble wall hung is a fire tube heat exchanger and an excellent product as i have done a couple of dozen with no problems. still haven't received any complaints after years of installs. uses a flat plate heat exchanger for hot water. If space is an issue this is the way to go.

I agree with @pedmec I have three of these in operation - one in my own home and they work very very well. Must do a combustion test to make sure the combustion is set to manufacturers specs and the unit will run great! On my tenant's Lochinvar Noble after 4 years in service just cleaned the inside of the fire tubes and shockingly the unit was very clean. It's a very reliable combi boiler.

Brian Tober

Noritz NRCB combi boilers are nice also. Made in Japan. I Have installed 2 systems, both jobs had existing fin tube baseboard. Both are running great for my customers.