OldSalt
Member
I wanted to pass on my experience with installation and use of a Tankless Hot Water Heater:
RECOMMENDATION: ADD A 50 MESH WATER STRAINER TO THE OUTLET SIDE OF THE TANKLESS WATER HEATER.
SECOND RECOMMENDATION: INSTALL THE FRIGGIN STRAINER ALREADY!!
I don't care what your water quality is, EVERY water heater will develop sediment. With tank'ed systems, the sediment generally settles to the bottom of the tank, while the hot water outlet is at the top of the tank. With tankless systems (at least, for the Rinnai), the hot water outlet is at the bottom of the unit, and there's no "tank" to hold the sediment. From the day the unit starts operating, debris WILL flow into your hot water pipes, and into your plumbing hardware. That includes your tankless hot water heater, if it's a recirculating unit. The Rinnai unit has a thimble sized strainer on the INTAKE side to protect the unit. However, a second, larger strainer is required on the outlet side to catch the junk that the unit introduces to your system.
All tankless water heaters require an annual backflush (for me, 3x or 4x annually), which is easily performed with an submersible water pump in a 5 gal bucket of white vinegar, two washer/dryer hoses, and using the backflush cut out valves. (My unit came with the valves installed, but kits can be purchased to add them if needed.) Our water was only warm to lukewarm after a year, when I first backflushed our unit (i.e. while I was diagnosing the sediment issue and adding the water jar style strainer). After the backflush, it's the full default 115F degrees, almost too hot to the touch.
I haven't seen that output line strainer on any manufacturers diagram (but my survey wasn't comprehensive), and I find that incredible. I can't imagine installing one of these units, with or without re circulation, without a strainer. The added bonus of the clear jar strainer is that I can "see" when it's time to backflush the unit, based upon the trapped sediment. My plumbing faucets and hardware fixtures are now mostly sediment free.
That's my review. I'll include links to strainers and my strainer storefront in my next post (just kidding, really!). Hope this helps some of you.
- Scott
- Background: New construction, new Rinnai RUR98IP (similar, RUR98E* and RUR98IN) tankless water heater installed by plumber. He was inexperienced with tankless w.h..
- Overall experience: Very good. Instant hot water with re-circulation, which puts hot water at every tap within two minutes (2200 sq ft house, 3 full bath, powder-room, kitchen, laundry with deep sink, exterior hot water tap). We have electric furnace/heat pump heating, and use propane for everything else (oven, stove, clothes dryer, fireplace). Average monthly propane cost (i.e. hot water was the biggest user) was 25 gallons. (Increased to 75 gal with addition of 30,000 BTU fireplace for main heat during cold weather below 30F, which is our heat pump's lock out temp.) We don't schedule hot water recirc for certain hours of the day, because "flipping the switch" on recirc delivers hot water everywhere in 30 seconds to 2 minutes max. Bottom line, VERY economical.
- Installation experience: Total nightmare. Problems included:
- Original plumber installed unit as "cross over", i.e. retrofit, even though we had a dedicated hot water re circulation line. Required 10 minutes to circulate hot water, versus less than 2 minutes using a dedicated (3/4") line, as recirc cross-over mode requires hot water to pass through a 1/2" faucet line "choke point". Plus, he didn't set the internal dip switches for cross-over.
- What the 30 year experienced plumber could not figure out, took me two minutes of reading to understand (plus one quick call to Rinnai technical support, which was excellent). I properly reinstalled the unit with an expansion tank and check valves, and set the dip switches.
- I've had the system apart and in pieces about six or eight times since original install. The largest problem I had was water quality. The water here in Northern Idaho is hard (not as hard as Southern California, but the result is similar). I had to clean out the intake filter once a week. I had cold water in the hot water lines. I added a whole house filter. I replaced it with a strainer. I had to clean sediment out of shower heads, faucet heads, and my clogged check valves (i.e. source of cold water in hot water lines). We had this sediment problem almost from the first day of operation, but I assumed the cause was the old city pipes.
RECOMMENDATION: ADD A 50 MESH WATER STRAINER TO THE OUTLET SIDE OF THE TANKLESS WATER HEATER.
SECOND RECOMMENDATION: INSTALL THE FRIGGIN STRAINER ALREADY!!
I don't care what your water quality is, EVERY water heater will develop sediment. With tank'ed systems, the sediment generally settles to the bottom of the tank, while the hot water outlet is at the top of the tank. With tankless systems (at least, for the Rinnai), the hot water outlet is at the bottom of the unit, and there's no "tank" to hold the sediment. From the day the unit starts operating, debris WILL flow into your hot water pipes, and into your plumbing hardware. That includes your tankless hot water heater, if it's a recirculating unit. The Rinnai unit has a thimble sized strainer on the INTAKE side to protect the unit. However, a second, larger strainer is required on the outlet side to catch the junk that the unit introduces to your system.
All tankless water heaters require an annual backflush (for me, 3x or 4x annually), which is easily performed with an submersible water pump in a 5 gal bucket of white vinegar, two washer/dryer hoses, and using the backflush cut out valves. (My unit came with the valves installed, but kits can be purchased to add them if needed.) Our water was only warm to lukewarm after a year, when I first backflushed our unit (i.e. while I was diagnosing the sediment issue and adding the water jar style strainer). After the backflush, it's the full default 115F degrees, almost too hot to the touch.
I haven't seen that output line strainer on any manufacturers diagram (but my survey wasn't comprehensive), and I find that incredible. I can't imagine installing one of these units, with or without re circulation, without a strainer. The added bonus of the clear jar strainer is that I can "see" when it's time to backflush the unit, based upon the trapped sediment. My plumbing faucets and hardware fixtures are now mostly sediment free.
That's my review. I'll include links to strainers and my strainer storefront in my next post (just kidding, really!). Hope this helps some of you.
- Scott