Phil May wrote:I just want warm water to pressure wash with. I also have a shower and hand sink in the shop. I was going to mix the water to the pressure washer so the hot would last longer. Would a 7 gpm coil keep up when washing. Also how much are they.
Unless your boiler is a monster I wouldn't think it could keep up while flowing at 7 gpm.
7gpm x 60 minutes/hr. = 420 gallons/hour
420 gal./hr x 8.333 lbs./gal = 3,500 lbs./hr.
3,500 lbs./hr. x 60 degrees of temp rise = 210,000 BTU's per hour required
Earlier today I ran my 3 GPM rated coil into my bathtub with the tubs hot water spigot wide open and it started out hot, but was cold (tepid at best) by the time the tub was about 3" deep, and the boiler fired up in a vain attempt to recover. Flow likely exceeded 3 GPM. I then took a shower in the same tub only a few minutes later and the water was hot the whole time. Flow must have been only 2 GPM or less.