Another tankless water heater replacing boiler thread

[OurTown]

From what I read a closed loop just means that it is not connected to a domestic water supply.

 

[cantbreak80]

This Glycol feeder will provide system pressurization...if you're so inclined.

 

[2Biz]

This Glycol feeder will provide system pressurization...if you're so inclined.

Maybe when its broken! LOL....Although, I have a flojet rigged up that will do the same thing! But thanks for the link!

As for required inspections per code...Code was written many years ago when condensing boilers wasn't in existance or very rare...It was designed around larger non-condensing boilers that was capable of running at temps that could possibly be dangerous...With the newer condensing heater/boilers we run them at temps that could never be an issue...Mine is set to 105°....Less than shower water! I think code should be re-written to allow for this type of heating system without inspections...

 

[HeyVern]

This Glycol feeder will provide system pressurization...if you're so inclined.

These are required by code here now. If the glycol level gets too low in the tank it shuts the boiler down.

 

[OurTown]

Could 2Biz's system run vented on the return line and still create enough pressure to run the heaters?

 

[2Biz]

I've thought about it! The only way it would work is to put the reservoir in the attic higher than the trough. The tank could be plumbed in line with the return line in the attic. It should keep the system full all the time. Then I would have to get up there and check level or rig up something else!!!

 

[2Biz]

The pressure is created by the two taco's inline to the heaters when they are running, so making it an open system has nothing to do with it as long as all 3 pumps stay flooded 100% of the time.

 

[OurTown]

I've thought about it! The only way it would work is to put the reservoir in the attic higher than the trough. The tank could be plumbed in line with the return line in the attic. It should keep the system full all the time. Then I would have to get up there and check level or rig up something else!!!

We could use electric heat tape instead of a hydronic loop for the attic trough.

 

[2Biz]

I have both!

 

[OurTown]

I have both!

Is the electric heat tape not enough?

 

[2Biz]

I hate freezeups! Even though its only happened twice in 13 years! LOL. I have gone to great lengths to make sure it doesn't happen! So a lot of times, if the temps get down in the mid to low 20's at night with day time temps in the 40's, my slabs can make it all night ice free. So I don't turn the floor heat on....The electric heat tape is always on below 32°....Having one of the floor heat zones running through the trough is redundant, but it is also a backup!!! I like to have backups!

 

[Zal]

Have you checked with Huron Valley? They always have a Navien triple unit set up at the car wash shows. They are very informative and offer full size boilers as well so they can tell you pros and cons. link is https://www.huronvalleysales.com/

 

[OurTown]

Have you checked with Huron Valley? They always have a Navien triple unit set up at the car wash shows. They are very informative and offer full size boilers as well so they can tell you pros and cons. link is https://www.huronvalleysales.com/

I called them 7 hours ago but had to leave a message. In the mean time I called Car Wash Boilers and also had to leave a message and still have not heard from them either. Since our wash was built by Super Wash I called them. They seem to have a lot of solutions to the 700 washes they built over the years. They told me they have good luck with the old Raypaks and very rarely need replacement. They have tried several different brands of tankless water heaters for floor heat and they have not proved reliable for them. They are still trying some others but the jury is still out on those. They really like the tankless water heaters on the self serve hot water though. Sometimes I run across bad reviews on tankless water heaters and really wonder if the issues are with improper venting or low gas pressures. (or some other installation issue)

 

[DakotaHoskins]

I just installed a carwashboilers unit for a customer. I was very impressed with the performance and build quality. Looking forward to replacing some of my raypack boilers.

 

[2Biz]

Propress makes for a clean (and Quick) install... Looks nice! What size (BTU) and model Navien is that? And how many sq ft is the customer heating?

 

[OurTown]

I'm now thinking of not going with a tank and circulator pump on the DHW. It would save so much space. In order to prevent pump starvation I could put in a second float valve plumbed with cold water in the gravity tank set a little lower. It is hard to tell how often it would be needed but would probably only be in the winter when the incoming water is cooler. I believe the plumber is installing a Rinnai CU199iN. Is there a simpler setup without using a tank and circulator pump?

 

[OurTown]

I called Huron Valley twice in the last two weeks and left messages with sales but no call back yet. John from Car Wash Boilers called back and I talked to him about our situation but he has yet to send me a quote. He suggested a double tankless stand setup for the DHW and a boiler for the floor heat. I'm sure we are talking big money.

 

[OurTown]

Could I or should I reuse the old reservoir for a buffer? I'm guessing it is about 5 gallons. If reusing it then it would be easy to show an inspector that it is an open air non pressurized setup. Currently there is one pump that pushes the glycol through the boiler and the tubing runs at the same time. Pretty much all the systems I see have a double loop system with one circuit running through the boiler and one for the manifolds/tubing runs. Would keeping the reservoir complicate the setup if going with a double loop system?

 

[cantbreak80]

ModCon boilers should always be configured with Primary/Secondary piping. ("Double loop")

The Primary circuit pumps through the boiler. The Secondary circuit pumps to the system.

Primary circuit is plumbed through closely spaced tees or a hydraulic separator. This design provides for boiler protection and creates the Point Of No Pressure Change (PONPC)...Google it.

Incorporating your reservoir/expansion/compression tank is acceptable and provides a fill port, sight glass, and convenient primary circuit temperature sensor well.

Here’s an installation featuring a Lochinvar wall-mount boiler, with closely spaced tees, Grundos pumps, and a tank. The system is operating with the fill port loosely installed…so, it’s basically and open system.


And it's Big Brother...heating approximately 7,500 sq.ft.


And you’re correct…it's big money! Pay Once...Cry Once.

 

[2Biz]

Here’s an installation featuring a Lochinvar wall-mount boiler, with closely spaced tees, Grundos pumps, and a tank. The system is operating with the fill port loosely installed…so, it’s basically and open system.
View attachment 10283 View attachment 10284 View attachment 10280 View attachment 10281 View attachment 10282

"The system is operating with the fill port loosely installed…so, it’s basically and open system". Could you explain this in a little more detail? How is this an open system?