Rinnai E50C

Tom_133

Anyone install any of these units yet? The project I am trying to get a handle on is this:



13 Condos all around 800 sqft and currently there are Laars Endurance EDP 110's in place which are way oversized as we all know. Also the units are getting their combustion air from the basement I believe and some have the stainless venting running up and out the sidewall and others go straight up through the roof. It's only a single bath and they are mostly just vacation homes. The down side is the LP feeds are 1/2" csst. Everyone unit struggles with Lock Outs all the time and they wanna change to something much less problematic.



My thinking is possibly a gas fired water heater with heating coil and atmospheric vented since it's in place. The other idea is the Rinnai E50C. Any ideas would be good, the heat loss is under 20K and there is a gas fire place that could cover the unit for heat but doesn't really heat the bedrooms, and the baseboard is already in place so hydronic heat makes sense.

Jack

It will

Fire 13,500-50,000. Hot water 2.1 gal @75* rise. You do not have to p/s if the heating loop is 4.6 ft head or less. LLH is available as an option if it is.

Tom_133

Jack

I am pulling the super problematic LAARS because of the lack of sufficient gas and quality of combustion air causing multiple units to lockout several times a day. I want to know if this E50C needs as much gas the on demands, seeing that it also has a 3/4 gas input.



I don't want any problems from these units after a week or two of running if you know what I mean, I basically want to make sure I install correctly so they don't haunt me.

Snowmelt

Tom

I would really look at the navien combo unit. How far is the gas run & what size meter. You will still need P/S.



Where are you located, if a single bathroom small condo it might be what you need. The gas valve is 3/4, but there made for retrofit so the first 15 feet can be 1/2 and it shouldn't lock out.

Tom_133

Price and BTU

Naviens are a bit more money and BTU's are much higher than I need. Even after modulating down it will probably short cycle on heat mode.

HDE_2

Not really

Navien's low fire on the small NCB combi is 13,000 BTU's and the Rinnai's Q50 is 13,600.

They are essentially the same.

I know the Navien 150,000 can be dialed down to 45,000 max input heating (30%) and then leave the domestic input alone or dial it down too, in either case the domestic flow on the Navien could be 3x better than the rinnai model.

Snowmelt

Thanks

HDE, thanks for pointing things out, I don't know why Tom thinks it will short cycle, are they just looking at the 160,000 btu like everyone else. It's a heating system nothing cheap on getting a nice all around heating system.

Just wondering why Tom thought it was going to short cycle. Why would he think the rinnai wouldn't short cycle.

The venting is also great with 2 inch venting.......

Or go with the product also advertise with this site the utica wall hung boiler with an indirect water heater.

SWEI

Do we have a chart or a table

showing thermal effeicency of the Navien at various firing rates and RWTs?  I'm still curious about this, and it bears directly on the system at hand.

Tom_133

Not detailed oriented

Snowmelt is right, I looked at the Navien but never noticed the down fire ratings. It's a possibility. Now it's price and if it will run on the current gas line. I will look into both today. The room its going in is only 3' x 3' so no boiler tank options.



Any thoughts on like a bradford white atmospheric vented with heating coil? I have never installed one but am curious if it would do the trick.

Jack

No, it will not use the gas

Required on a tankless. It is a max 50kbtu. I cannot answer your gas supply and CA requirement issue. You have to calculate that and provide it regardless of the product you choose. 3x the hot water is excess capacity when you need 1x the hot water. The 2.1 gpm at 75* rise will mix to about 2.5 at use temp. In a 1-1.5 bath place that should be sufficient. Also, within the 4.6ft head the E50C does not require PS piping. That means you use the provided boiler pump to drive the system. You don't need the second circ, relay control, parts and labor to do the p/s job. You have 2* temp increments! not 20*. A robust ODR included. 96% eff. It comes set up for PVC venting, but you can adapt it to the poly prop concentric (5"OD) if desired. That is the right way to eliminate CA issues. Personally, I like outdoor air for everything. I've had tremendous success with Rinnai products over the years and one of the keys to the reliability has been sealed combustion direct venting.

Do your due diligence and let us know which way you go.

Tom_133

So just as an update to this thread:

I have since installed 5 of these units and so far they are all doing very good. One of them was hitting temp during a shower because the shower head was so clogged that it wasn't allowing enough flow to keep the boiler firing, which meant a 30 second cool period in the shower.

Only two complaints:
1 the aeration period is rough to sit through.
2 the way rinnai adapts to the piping on the bottom. The compression fittings are definitely not as clean as straight copper take offs. This is just my preference, has never been a real problem. A little more room between pipes would help as well.

kcopp

Could you not have converted the gas piping to a 2# system? installing a maxitrol 325 at each unit? You would have plenty of gas then....

Alan (California Radiant) Forbes

I hear you on all your points (aeration time, close distance between fittings and compression connectors); very difficult to get a wrench in there.

The instructions are abysmal as well.

However, all in all once they are installed, they work pretty damn well. Sure wish they had 2" venting, though.

Jack

There is a work around on the aeration time. I'll dig it up and post it.

Tom_133

Jack, if you pull that off we will eat like kings!