Does Yosemite have a problem reaching alternate subnets?
No - I've not had any issues with 10.10 or 10.11 with multiple subnets, multiple IP address per host and multiple network interfaces on a single OS/Mac.

I'd think something else is up. Are you familiar with the bonjour utility:

dns-sd -B _http
dns-sd -B _ipp


You can take the instance name and then dig up the IP address and cross reference it with arp -a to figure out many printing network issues...

mac:~ me$ dns-sd -L "Living Room HP D110" _ipp local.
Lookup Living Room HP D110._ipp._tcp.local.
DATE: ---Sat 28 Nov 2015---
12:44:33.139  ...STARTING...
12:44:33.584  Living\032Room\032HP\032D110._ipp._tcp.local. can be reached at hp.local.:631 (interface 4)
 txtvers=1 qtotal=1 pdl=application/vnd.hp-PCL,image/urf,image/jpeg rp=ipp/printer URF=CP1,MT1-2-8-9-10-11,OB9,OFU0,PQ3-4-5,RS300-600,SRGB24,W8,IS1 ty=Photosmart\ D110\ series product=\(HP\ Photosmart\ D110\ series\) usb_MFG=HP usb_MDL=Photosmart\ D110\ series priority=60 mac=68:b5:99:3e:a3:8b adminurl=http://hp.local. note=Family\ Room Color=T Duplex=F Scan=T
^C


Also, pings are the first packets to get dropped in most network overload scenarios, so try telnet on a known port (80 or 631 in this case) to get a reliable indication of health of the printer or device on the network.

You might need to handle IPv6 and IPv4 versions of the tools, too. (ping6 and telnet -6)