Hi Russ!
Yes, those Sharkbite Max fittings are fantastic!
A real game changer!
I’ve been using them professionally and on personal projects since they came out.
Industrially there are several types that are also great for the 1/2” and less diameter tubing like those made by SMC but Sharkbite did their homework for the 1/2” and up diameter general plumbing.
I’ve had several Sharkbite installations on other hydronic heating systems that have performed flawlessly for over a decade.
Both on copper, stainless, PVC and PEX piping.
The key is always in the preparation… square the cut ends, full chamfer of the ends and de-burr, NO linear scratches, measure/mark the proper insertion depth.
I like to also add a very thin coating of Vaseline Petroleum Jelly on the pipe ends prior to insertion to the fittings.
They also have the advantage of some flexibility/rotation after installation unlike a lot of regular PEX expansion fittings.
Regular PEX expansion joints can become time consuming and are basically one shot assembly.
If your careful one can undo/redo Sharkbite connectors a couple of times IF need be.
I used to do a lot of copper pipe sweat (solder) joints. THAT can be time consuming and exacting. Also difficult to adjust when needed.
Up side to solder joints are they can be extremely durable … expecially when doing silver solder joints… for very high temperature industrial type process applications.
When it comes to the more practical aspects of home plumbing where one is dealing with below 212 deg F water and/or hydronic applications the options available now are great.
Now back the the new heating system….
Our 25+ year old old tied Trane combi-boiler system was finally put out of its misery last December (just in time for the Holidays
). We’d been considering replacing this old system for the past couple of years and gotten several replacement combi-boiler quotes which ranged from a low of $8k to a high of $15k!!! These were non-crisis summertime replacement quotes, not emergency “Holiday” replacement quotes.
One of the things I found most annoying over the past decade was the need to shell out annually $450 for the service technician never mind the problem calls that inevitably occurred… as there wasn’t much that was home owner serviceable to be honest…so generally $1000/year.
This is where I got out my design engineering hat back out and decided to take the ‘opportunity’ to get some actual data to make a better informed decision.
Our northern home is a small chalet style 1600 sq.ft. two story with lots of western facing windows.
Standard 2x4 stud wall construction with kinda cathedral 1-1/2 story second floor ceilings.
I tested the actual heat load requirements by using three electric thermostatic portable heaters all last winter.
Each of the heaters were 750/1500 Watt capacity and were each limited to the 750 Watt max setting.
Each was set to cycle off at 65 deg F.
The second floor heater barely ran at all last winter.
The first floor heater ran about 30-40% of the time.
The basement heater ran about the same as the first floor.
The house stayed consistently at 65 deg F throughout the winter.
This gave me a practical actual thermal perspective of what the house actually needed for a baseline.
Note: The propane heating system was disabled and turned off entirely.
I confirmed the power consumption with our electric bills and cross referenced with the daily actual outside air temperatures.
I confirmed the interior house temperature via actual thermometer and the house video system.
The time frame was January/February/March/April while we were down south in SC.
During two extended power outages which each lasted several days the residual heat saturation of the home and solar loading the house did not go below 55 deg F. Thermal recovery after power restoration was within 3 hours.
To simplify things I calculated the actual peak thermal requirement at 3 x 1500 Watts = 4500 Watts.
Converting Watts to BTU/h is 1 W is equal to 3.41 BTU/h… 4500 Watts x 3.41 = 15,345 BTU/h.
This is roughly more than twice what the actual heat requirement for the home so it’s really on the conservative side.
Sooo… knowing all this it allowed me to objectively look at what was really needed vs what the furnace and plumbers were proposing.
All the proposals were for 100k to 180k BTU/h systems.
Actual requirement is for a demonstrated need of less than 15k BTU/h.
Big difference.
The proposed systems run at hydronic fluid temperatures of 185 deg F for baseboard radiators.
None of the proposed systems would have a thermal fluid reservoir, so it them to fire up repeatedly for every heat demand call.
This results in high cyclical rates of short durations… generally that results in increased mechanical and thermal stressing.
While all the proposed systems were rated as high efficiency systems the actual propane consumption of the ‘new’ systems vs the 25+ year ‘old’ system was less than $150/year. Not much of an annual savings to be honest.
So I decided to go with a 40 gallon blower vented 50k BTU/h high efficiency propane hot water heater as a dedicated hydronic system heater utilizing 100% hydronic heat transfer fluid (RhoGard). The water heater temperature range maxes out at 155 deg F (but we’d be running it at about 120 deg F). This is a closed loop system serving 4 specific service zone loops. This is roughly more than 3+ times what is needed at max actual requirements.
Zone 1: 1st Floor and Basement
Zone 2: 2nd Floor
Zone 3: Domestic Hot Water multi plate stainless steel isolation heat exchanger with tempering system (to avoid scalding)
Zone 4: Recirculating loop when there are no other system demands. This keeps the water tank from stratifying allowing for a consistent thermal fluid mass.
All up the replacement system designed costs less than roughly $3k all up for materials.
Estimated operational propane cost calculates out (very conservatively) at about the same as our 25+ year old system that crapped out.
So the as designed system is saving us about $5k to $12k vs. the multiple proposed systems.
Here are several consideration notes:
Note 1: All the proposed systems had functional warranties of 5 years or less.
Note 2: All the proposed systems would require a professional service technician servicing annually. So at a minimum $450/yr x 5yrs = $2,250.
Note 3: Fuel cost savings of proposed systems vs. designed is roughly $150/year. So that equates to $150/yr x 5 yrs = $750 over 5 years.
Note 4: The Designed system water heater costs less than $1k.
Note 5: The Designed system 40 gallon water heater has a standard geometry so that means it can be readily replaced with whatever availability unit is current in the future without duress.
Note 6: The Designed system standard blower type propane Water heaters are nearly bullet proof and typically don’t require much if any servicing. What annual servicing is needed is readily accomplished by a home owner. They also typically have 3 to 5 year warranties.
Note 7: The Designed system utilizing a heat exchanger provides unlimited hot water on demand.
Summary:
Not only does this Designed system have more than sufficient heating capacity to meet demonstrated needs it also has an initial up-front cost that is considerably less than any of the proposed systems by about $5k to $12k. While the potential operational fuel costs of the Designed system may cost more than the proposed systems it only amounts to about $750 over 5 years. (Still this is much less than the up-front proposed systems costs. ) Then the annual technical service visits for the proposed systems adds up to about $2,250 over 5 years. This places the Designed system in a pretty good position overall both in the near term for purchase cost but also for the long term.
It’s important to note that this Designed system is a “closed loop” system and ‘does not directly heat potable Domestic Hot Water’.
Any limitation of using a water heater as a hydronic loop system heater is when people attempt to use potable water to directly provide hydronic heat and Domestic hot water with the potable water, this would be an “open loop” system. Open loop systems are/can be problematic as the ‘potable water’ can sit for extended time in the hydronic loop potentially growing legionella type contamination.
A closed loop system does not have that problem.
Best Regards,
Over Easy
I’ll be monitoring the system now that it’s operational and provide updates on how it performs.
One of the things that this project has done has gotten me thinking about how I could possibly adapt this to a hydronic heating system for our boat for early and late season cruising. This would keep any fuel combustion safely outside of the cabin. It would free us from needing shore power or generator power for cabin heat. (We have a flame free boat cabin mantra… the years spent as a city medic and dealing with burn victims makes this a hard rule for us.)
