I purchased my Hayward H250FDN to replace a ten-year old version of the same machine that was destroyed by a direct lightning strike. The old unit had just received a new combustion blower a few months earlier and was operating perfectly up to the evening it was killed. Other than the combustion blower, I had zero problems with the machine over a ten-year period, and that made the decision to purchase another one easy. Now, I must explain that I am in a unique position to write this review, as I am the installer, the end user, and a former trade mechanic.

I started shopping for a replacement heater a few hours after realizing my old one was D.O.A. Just as I found ten years ago, the H250FDN is much cheaper on the west coast. I paid nearly $200 for shipping and still saved hundreds versus what I would have paid from a local east coast distributor.  The unit arrived and the first thing I noticed was that the factory packaging is quite sufficient and easily survived the coast-to-coast ride. The drop-shipped unit arrived packed on a pallet and surrounded with thick cardboard, completely undamaged and in pristine condition.

The Hayward Low NOX pool heaters are designed and manufactured to meet rigid emission standards in many states, however that doesn’t preclude you from owning one just because your state hasn’t caught on yet. You see, the secret to building a clean-burning gas appliance is in the quality of the controls. When I opened up my H250FDN heater prior to installing it, I immediately recognized many of the components from my days installing high-end condensing furnaces. There’s a forced draft system that eliminates environmentally induced combustion air issues. The hot surface igniter eliminates pilot problems. On board diagnostics will point to a problem if one arises. The control panel is simple and requires no instruction to operate, and the unit has a footprint small enough to fit where an ordinary pool pump would go – it’s a mere 28” wide and 24” high.

Hayward got many things right with this machine. It comes wired for 220VAC and can be easily converted to 110VAC by replacing a provided jumper. The electrical connections can be made on either the right of left side of the unit, and there are provisions for remote thermostats and a fireman switch. The heat exchanger can be rotated so that the fittings are on the left or right. There are four plastic feet below that keep the base a few inches off the ground; higher than my old machine, but the lower profile does not suffer.  This mean no debris or animals underneath. The cabinet is solid and there are no gaps for insects or rodents to infiltrate, though they always seem to find a way!  With all this considered, I’m baffled as to why there are no provisions for reversing the gas supply. This is a surprise given the flexibility of the rest of the machine.  There isn’t even enough room inside the unit to swing the gas line; I actually had to pipe completely around the unit – very disappointing.

On the bright side, the parts that comprise the burner and control section appear to standard industry pieces (read: less expensive) instead of the custom-looking parts in my old machine. This is a good thing, as replacement cost will not be prohibitive should something fail. The circuit board is now three small pieces instead of one large one, and all three have small automotive-type fuses on them. Replacement fuses are also provided in a small pouch inside the unit.  I’ve got to wonder if this unit would have survived the lightening strike that killed my old one.

It took me about two hours to get the unit placed, wired, piped, and running.  Half-unions are provided for connecting the polymer heat exchanger header to the pool piping, but the nipples are 2 ½” O.D. and 2” I.D. – much larger than typical pool plumbing, and there are no reducing bushings provided. I had to take a ride to the local hardware store for a pair of 2” x 1½” bushings in order to make the connections. Once the glue dried I purged the water and gas lines and fired the unit. 

Once energized, the circuitry runs some internal checks before the inducer fan starts.  After a 30-second combustion chamber purge and igniter warmup, the main gas opens while the inducers slows for a second – a nice feature surely intended to optimize ignition and quiet the initial firing of the burner, something that my old unit was quite loud about.  Once running, the unit emits a low rumble that is not an issue outdoors, however I imagine it might be a bit loud if used indoors with the proper vent kit. Otherwise, there are no unusual of excessive noises and I am barely aware of the running unit from 20’.

My pool temperature started at 72.  I set the heater for 84 and let it run.  I observed temperature rises of roughly 2 degrees per hour with my 18’x 33’x52” above ground pool – in line with what the old unit provided.

Hayward has certainly done some homework and made improvements to this already excellent line of pool heaters. Still, I am truly at a loss to explain why they would offer flexibility in voltage, plumbing, and wiring, yet leave the gas supply fixed.  This is a problem for the installer, and that additional cost will be passed along to the end user. The bottom line still makes this piece of equipment a stellar choice given the cost and reliability factors. That is, provided lightning doesn’t strike twice!

Recommended: Yes