Kevin Mark Klughart
PhD, PE, JD, MIP, LLM
Patent Attorney / Engineer
My friend James and his wife purchased a fixer-upper house that needed a complete pluming retrofit. We tore up the kitchen floor and some interior walls to expose the old plumbing and it turned out that the old galvanized pipe had completely rotted through in some areas. The best long term solution to this was to rip out all the old plumbing and replace it with new copper. With just a little instruction James was able to plumb the bathroom and I worked on the main lines in the kitchen. I've never seen someone work so hard to fix up a house - the effort by James was awesome, and the final results were impressive!
Since we had to replace everything, including the water heater, it seemed a good idea to install a tankless water heater. Nothing special about this, but the twist you will notice in the following photos is the steel supporting frame I fabbed up to hold both the water heater and the valves necessary to implement the system. This support structure permits easy attachment of the system to the wall while maintaining seafety clearances required by the manufacturer. It also permits clamping of the plumbing manifold, recirculating pump, and electric to prevent damage during and after installation.
Here you can get a good look at the gas line input on the right, the On/Off switch, cold water input line, hot water T&P valve, and the hot water output. Note that the system is configured to permit removal of the hot water heater and draining of the system with appropriate ball valves.
Here you get a good look at the control valves for the system as well as the provisions for a hot water recirculating pump. Some tankless systems don't support hot water recirculation, but the TAKAGI MOBIUS T-M1 Tankless Water Heater (http://www.takagi.com/) does support this if properly installed. Just below and above the pump you will see cutoff valves to permit removal of the pump for replacement if necessary. Above the upper cutoff valve you will see a one-way butterfly valve - a corresponding one for the cold water input is immediately to its right. Also, note the two valves just below and to the left and right of the T&P valve. These can be used to drain the system for maintenance/removal of the tankless hot water heater.
For those of you interested in how the recirculating pump system works with this configuration, the following diagram should provide all you need to implement this in your situation. Note that a number of cutoff/service valves included in my implementation are not shown in this diagram.
In gathering together the info for this page I have noticed that TAKAGI doesn't make the T-M1 model anymore, opting for even more efficient (95%) systems such as the T-H1/T-M32. Depending on you requirements, one of the systems offered by this company will do the job. The T-M1 systems could be cascaded together for higher flow rates as well as to support system redundancy. This same feature is available with their newer more efficient units.
Kevin Mark Klughart
Registered Patent Attorney, USPTO
3825 Leisure Lane, Denton, TX 76210-5589
tel: 800-353-1211 / 940-320-0580 - fax 940-320-0581