View Full Version : Please Help: Confusion over Sprinter Heating Options

03-30-2011, 12:11 PM
I have a question regarding heating options on the Sprinter (to be a 2011 or 2012 model, high-roof, 144-inch WB):

My goal is to have the passengers ride in comfort throughout normal temperature ranges experienced in the United States, not unlike most cars. As the passenger compartment is a fairly large space, it made sense to include a rear A/C unit, I therefore am of the mind that heating is much the same and might require an additional unit. In addition, the thermal properties of the high efficiency diesel engine do not reach the temperatures of a gasoline engine, and therefore will not be as great at heating.

My confusion originates from the myriad of heating choices when ordering a Sprinter. I currently have four choices:

PH3 (Rear Heating Package I) includes:
H01 (Insulation for Rear Compartment): additional insulation in the sidewalls.
H04 (Insulation for Front Compartment): additional insulation in the sidewalls.
HZ9 (Heater Booster 5kW): 5-kW heater booster can be switched on whenever the engine is running. The on/off switch is situated to the right of the light switch. When the heater booster is switched on, a red indicator light comes on in the switch and a symbol lights up in the instrument cluster. After the heater booster has been switched off, the coolant pump and the burner blower continue running for approximately 3 minutes, then switch off automatically.
H13 (Heater – Auxiliary Rear): An auxiliary heat exchanger is connected to the water circuit in parallel with the front-end heat exchanger. The heat exchanger is installed under the floor behind the B-pillar, on the left-hand side of the vehicle. The control panel, with controls for temperature and air volume, is situated in the instrument panel. The warm air is routed upwards through the floor panel and enters the load compartment/passenger compartment via a duct bolted to the wood floor. The auxiliary heat exchanger can only be switched on when the engine is running.
PH4 (Rear Heating Package II) includes:
H01 (Insulation for Rear Compartment): see PH3
H04 (Insulation for Front Compartment): see PH3
H12 (Heater – Auxiliary Front 5kW): A fuel-powered 5-kW auxiliary heater is mounted under the floor in the area of the left-hand B-pillar. The auxiliary heater warms the coolant, which then heats the driver’s section via the water circuit of the front-end heater. The air is supplied to the interior via the air outlets in the instrument panel. The auxiliary heater is programmed via the instrument cluster using the adjusting knobs - on vehicles with standard instrument cluster - or the steering-wheel buttons - on vehicles with multifunction steering wheel (Code CL4) and pixel matrix instrument cluster (Code JK3). Maximum operating time is 60 minutes, at which point the heater switches off automatically. When the engine is running, the auxiliary heater can be turned on as a booster, using the switch, to supplement the front-end heater. When stationary heating mode terminates, the heater automatically switches to booster mode
H13 (Heater – Auxiliary Rear): see PH3
PH5 (Rear Heating Package III) includes:
H01 (Insulation for Rear Compartment): see PH3
H04 (Insulation for Front Compartment): see PH3
H13 (Heater – Auxiliary Rear): see PH3
HY1 (Remote Control for Auxiliary Heater): The radio remote control can be used to switch the auxiliary heaters (H12 or HZ5) on and off. It has a maximum range of approx. 600 metres. This range can be reduced by proximity to interference sources, by any large obstruction between the remote control and the vehicle, by unfavourable positioning of the remote control or if the latter is used from inside a closed space. Maximum heater operating time is 60 minutes. When the auxiliary heater is switched off using the remote control, the burner blower (H12 + HZ5) and the coolant pump (H12 only) continue running for approx. 3 minutes.
HZ5 (Water Auxiliary Heater with Timer): The dual-function water auxiliary heater operates both as a heater booster and as an auxiliary (stationary) heater. The booster (10 kW) mode is activated automatically as a function of coolant temperature, whenever the engine is switched on. An indicator light comes on whenever the booster function is active. When the engine has been switched off, the heater booster continues running for approx. 2 minutes. The auxiliary heater (5 kW) can be switched on by means of a switch with indicator light. The indicator light comes on whenever this function is active. Maximum heating time is anything up to 2 hours, depending amongst other things on coolant temperature. The auxiliary heater continues to run for 15 minutes after the engine has been switched off. If both the auxiliary heater and heater booster functions are activated, the auxiliary heater has priority. After the auxiliary heater function has been switched off, either manually or automatically, the heater booster is activated automatically.
PH7 (Auxiliary Heating Package) includes:
H12 (Heater – Auxiliary Front 5kW): see PH4
H88 (Rear Heater Prep): Two water lines (supply line/return line) are routed under the floor panel on the left-hand side of the vehicle, extending aft of the B-pillar. The ends of the two lines are connected by a hose. Bodywork modifications for installation of a heat exchanger, the aperture in the wood floor for the warm air ducting and electrical parts are not included.
For my purposes, it seems that PH4 would be the best options, yet this is further complicated by the notes in the MB configurator.

PH3 comes with the note “Note: due to 2010 CARB regulations the heater booster only operates at out-side temperatures below <39.5 degrees F.” I assume this notes is referring to HZ9.

PH4 comes with the note “Note: due to 2010 CARB regulations the aux. front heater only operates at out-side temperatures below <39.5 degrees F.” I assume this notes is referring to H12.

PH5 comes with the note “Note: due to 2010 CARB regulations the water aux. heater only operates at out-side temperatures below <39.5 degrees F.” I assume this notes is referring to HZ5.

PH7 has no notes associated with it. In addition, this confuses me as the H12 is in both PH4 and PH7, with the note only appearing for PH4.

This presents me with 3 out of 4 possible heater options not even functional above 40 degrees F. I want a heater that will function when I want it to function, whether that be 40 degrees, 50 degrees, or 60 degrees. I do not want to pay for a heater that will not function 11 months out of 12.

Does anyone out there have opinions or experience with any of these heater options, or perhaps more complete knowledge of these 2010 CARB regulations and why they prevent me from operating a heater? Perhaps no additional heating is required? I appreciate any and all input. Thank you in advance.

03-30-2011, 03:36 PM
If your choice includes H13 (PH3,4,5), then I think you will meet your goal of keeping your passengers comfortable if the engine is running at outside temperatures above those where CARB rules limit use of the diesel-fired (booster/auxillary) heater. H13 is essentially the same as the heater unit in the dash - a heater core and air mover for the rear compartment. I have an earlier version similar to PH4 and it works well for me.

Graphite Dave
03-30-2011, 04:29 PM
Consider buying a real Espar water heater instead of one cobbled by Mercedes. I have the Mercedes one and would not buy it again. Mercedes now limits its use to 39 degrees and below which would eliminate most of the time I use it to defrost the windshield and warm the interior on cold mornings on my 08. Mercedes also limits its run time. Investigate having an Espar dealer install a real Espar water heater after you take delivery. You could then run it at any temperature for as long as you want. The other benefits are the ability to include the 7 day timer with diagostics and the ability to have it repaired by an Espar service center. The heater is supposed to be run once a month to keep it functional. How do you do that in the summer when temperatures are above 39 degrees? I wanted the heater for heating and hot water for a shower. If you only need it to heat air, then the Espar air heater may be the best option. There are a bunch of posts talking about the air heater. Seems everyone is very happy with the air heater.

03-30-2011, 05:23 PM
We have basically the PH4 option above, with the programmable fuel fired heater and the rear heater element. We rarely start the auxiliary fuel fired heater, except to warm things up when it's very cold outside (below freezing). The rear heater core will keep the rear as warm as you need even without the aux. heater running. If you live in a very cold climate, you might need additional heat for around town or if you idle a lot (not recommended), but even on the mountain in cold (10 degrees F) i have never needed the fuel fired heater while driving.
If i had to order it again, now that i have experienced what these components do, i would order just the rear heater core. Since i installed the Espar D2 Airtronic, all of my rear heating problems are taken care of. Especially when i live in it for any length of time.
Hope this helps

03-31-2011, 03:25 PM
Thank you to all.

My dealer tried to help me as well by asking the U.S. rep in Germany, and this is what we got back:

"Sometimes things that are important to Europeans mean nothing to Americans, and this is one of those things. In Northern Europe, we put “fuel fired heaters” that run with or without the engine to produce more heat than a standard automotive heater, that blows air across a heater core heated by engine coolant, just like cars and American trucks. The ability to use Sprinters as a place to warm up workers on job sites, etc…, is common in Europe as an example. When EPA in the US revised their criteria in 2010 for those types of heaters, they were restricted to extreme cold climate, Canada, Alaska, etc.., because the fuel exhaust isn’t routed through the converter for processing with the new Urea based cleaner exhaust, and therefore could if run continuously produce excessive emissions…For general useage, the PH7 rear heater option is what a passenger van consumer will prefer, it has an independent fan control, and floor vents so the heat comes out of the floor and circulates upward."

So, for normal useage the PH7 option should work fine. Maybe. What confuses me is the MB rep saying it has floor vents, when the handy option guide I downloaded from these forums specifically notes that no dody work or venting is done for this option...it's merely a front heater booster with pre-wiring/hose lines installed for any future rear heater.

So, anyone with the PH7 option able to verify it's capability, efficiency, adequacy, what have you? Is it overly noisey or any other short comings of the system? Thank you, all, so much for the wealth of knowledge and helpfulness you offer here.

Graphite Dave
03-31-2011, 03:58 PM
My 08 has what is now termed the PH7 option. I have the 5kw diesel water heater with the rear heat prep option. What that gives you is the Espar that has been modified by Mercedes (water pump removed) and the two 18m pipes going toward the back. The heater is controlled by a combination switch to the left of the steering column. You push the top half of the switch to start the heater without the engine running. The dashboard heating temperature dial must be set higher than the ambient temperature or the Espar will not start. The lower half of the switch will start the Espar with the engine running. The purpose of using the Espar with the engine running is to heat the engine water if it is so cold the diesel engine can not get up to operating temperature. Of course Mercedes in their wisdom does not give you a water temperature gage so you have no way of knowing if you should start the Espar with the engine running. The two 18mm water supply and return pipes go toward the back and make a 90 degree bend so they are aimed at the rear floor behind the driver seat. There are no holes in the floor. The pipes terminate about 6" below the floor and are connected with a 180 degree "U" rubber hose. The two tubes are hot when the Espar is running and also hot with Espar off and the vehicle engine is running.
I repeat my earlier comment. I would not buy the Espar from Mercedes. The 39 degree limitation, 2 hour run time limit and lack of a 7 day timer would make me buy a real Espar after taking delivery and have it installed by an Espar dealer. The other problem you will have with the 39 degree limitation is the inability to run the Espar once a month to keep it servicable. I guess you could pack the temperature sensor with ice to be able to run the unit in the summer. If all you want is rear heat and do not need hot water for a shower, the best solution is probably the Espar D2 air heater. Smaller, guieter, uses less power and simpler with service available from Espar service centers.

03-31-2011, 04:05 PM
So, for normal useage the PH7 option should work fine.

IF your OP description of PH7 is accurate, then PH7 won't give you what you want. Seems to me you need to make doubly sure (point out the discrepancy between the two descriptions to MB) of the actual scope of PH7. Depending on the outside temperatures you might encounter, the diesel-fired booster or booster/auxillary heater could be a good addition since in usage around town in outside temperatures below about 30F it has proven to be very useful for me.

03-31-2011, 05:04 PM
Seems like the option for just the rear heater would be H13. That would be sufficient to keep the rear warm in most driving situations, albeit with some noise involved. It really isn't that much noisier than running the front blower.
The best use i have had of the rear heater was when the front blower motor died. The rear heater running on high provided enough heat to keep us comfy, but unfortunately couldn't keep the windshield clear. That was done with towels until we reached freeway speeds and the air moving through the system became almost enough to do the job.

Graphite Dave
03-31-2011, 05:36 PM
Read hkpierce posting "proheat air diesel cabin heater" for another air heater choice. The other point I meant to make was your passengers could be cold when outside temperatures are above 39 degrees and diesel heater will not start.

04-01-2011, 12:53 AM
Just a Quick note on the H13 heater, it would not hurt to install a steel shield over the plastic housing around this heater underneith your van, mine had a few rocks bust holes in the housing shorting out the module inside because water splashing up from the driverside front tire got in.To repair it is to replace it. For the booster heater it works great very handy with the remote control!

09-21-2017, 04:47 PM
Hi all, does anyone have experience on removing that rear aux heater on the floor of the Sprinter van (drivers' side)...? Some rocks broke that plastic housing allowing water to get up in there and (I'm guessing) shorted out the blower motor. I have a replacement Bosch blower motor in hand, just need to know how to take that plastic box out so I can put this new blower motor in. Any tips, etc are much appreciated. Thanks in advance.

FYI, this is the best image I've found of the unit in question: