Surge protection for on-demand, exterior, tankless water heaters

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joanie said:
The system for tankless water heaters contains some electronic controls. How does one protect the controls of these natural gas-supplied water heaters from power and lightning surges? Is there a certain type of surge suppressive device? Thank you
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They are either hard wired or plugged into a receptacle outlet. Standard surge protection for that circuit or outlet should be all that is required.
My only other concern is to confirm that the gas pipe also be properly bonded to ground somewhere along the way. If not, then surge suppression at the outlet may not be enough to protect the innards.
 
Surge protection for on-demand, exterior, tankless water heatersrs

Surge protection for on-demand, exterior, tankless water heatersrs

It is plugged into a receptacle that is protected from the elements, but the cover is clear. Since the gas installer is licensed for work on gas lines, should he not be familiar with the grounding requirements and with the requirement for surge suppression, or do they just install what the customer tells them to install?
 
joanie said:
It is plugged into a receptacle that is protected from the elements, but the cover is clear. Since the gas installer is licensed for work on gas lines, should he not be familiar with the grounding requirements and with the requirement for surge suppression, or do they just install what the customer tells them to install?
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There is a requirement for surge suppression only if the manufacturer's instructions contain that requirement. Beyond that it is just good design practice. I am assuming that the gas installer did not put in the receptacle!
As for the grounding of the gas line, yes the gas installer should be aware of that, but if he is connecting to an existing gas line he may well assume that the original installation was properly grounded and just add his pipe to it.
 
IMO the best attack is 2 or 3 prong attack. Well not just my opinion but IEEE and the whole engineering community. TVSS is divided into 3 classes of A. B, and C.

Class C is Service Entrance devices sometimes called Whole House protectors and the most effective are just 3-modes for single phase service connected between L-L, L1-N, and L2-N. The other 3 modes L1-G, L2-G, and N-G are NOT NEEDED and a waste of money and material. The required N-G bond at the meter negates their use. No SPD can handle as much energy as a bolted fault. Look for Models with UL 1449 Second Edition and a minimum of 70 Kva/mode. 200 Kva typical. The bigger the better. Ignore Joules ratings

Class B is for Sub Panels and no need to discuss for most residential applications as they do not normally have Sub panels beyond the Main panel.

Class A is Point of Use. Look for 5 modes, UL 1449 Second Addition, 15 Kva /mode minimum. Like any class bigger is better. Ignore joules. Kva is what you look for.

OK here is the meat on the bone. If you only do just one TVSS device, do it at the Service Entrance. 99% of all surges come via the utility differential mode. A Class A device at Point of Use just does not have enough capacity to take TVSS events from the utility. The Class C absorbs most of the energy, what does get through can then be handled down stream by the Class A device.

Last tid-bits is look for buit-in TVSS. The most effective Service Entrance TXSS are the Meter Collar type where you unplug the meter, plug in the TVSS, and then plug in the meter. Next in line for Class C is either built into the Main Panel bolted between the busses, or dual pole that are plugged into Dual ganged circuit breaker slot. Last is add-on to side of Main Panel keeping leads tightly twisted, straight and short as possible.

For Class POU built in the receptacle and invisible other than indicator lights.
 
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Surge protection for on-demand, exterior, tankless water heaters

The gas company ran a new natural gas line from across the street to the home. I'm sure the gas company grounded the gas line correctly.

The contractor installed the exterior receptacle, the tankless water heater and everything from the gas service (meter) to the tankless water heater. He ran the new hot and cold water lines through the exterior wall, across the attic floor, and down through the ceiling to the existing hot and cold water lines where the water heater was and back up through the ceiling (very ugly in laundry room) to the rooms requiring hot water.

Anyway, bottom line is, I just need to have an electrician install surge suppression at the main distribution panel, not at the water heater receptacle, too?

Thanks for your help.
 
Welcome back Dereck!
And a simple way to look at this is
You get what you pay for.
More is better.

Yes have an electrican install a TVSS at the main panel. Expect to pay $300-$400 for the device.
Then a receptacle type, where the demand water heater plugs in

I just had a Navion tankless heater installed, its great, but inside are a lot of electronics - I will post a picture.
I have a main panel TVSS, and am going to install TVSS circuit breakers and a TVSS receptacle.
 
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